My Two Cents

[NeotrekkerZ]

although
between (preposition)
Body Parts (hands, feet, hair, face, head, toes, chest, waist, mouth, neck, shoulders)
cold (in relation to temperature)
Colors
light, dark, bright, dim, brilliant/vibrant, deep (relating to colors)
cute (describing a person)
darkness (antonym of atan)
Directions
Don't worry about it/ne t'en fait pas in French (idiom)
dry
elegant
enemy
enjoyable
excited
faith/belief
family
food
friendly
glow/glowing/to glow
Good morning (idiom)
happy (describing a person)
heavy (weight)
hungry/hunger
I apologize/my apologies/I'm sorry (idiom)
later
light (weight)
moon
old (antonym of 'ewan)
on/onto, into (prepositions)
rarely (antonym of pxìm)
sad (describing a person)
sea/lake
See you later (colloquial good-bye idiom)
sentence/phrase
should (conditional of shall)
smart
somehow
sooner
story
Superlative Construction
Tastes (and to taste)
to be mistaken
to do
to enjoy
to excite
to fix/improve/make better
to hate
to hold (cradle, hold in your arms, hold your hand)  
to like (someone or something)
to quiet
to remember
to sit
to wake up/awaken
to wonder
thirsty/thirst
through
ugly (antonyms of sevin and lor)
water
wet
wisdom
wise
You're welcome (idiom)
*If tìrol is "song" what's "singing" (as a gerund/noun)

cold ( in relation to disposition)
mine/yours/his/hers/ours/theirs
shallow/superficial
shiny
sunrise
sunset
talkative/chatty
tired (for a person)
to prohibit (antonym of tung)
to regret
vulnerable
warm (in relation to disposition)
windy (as in a windy/breezy day)
Something like "doch" in German

leaf
mercy
shadow
to diminish/lessen
to dream
to soar
to rain
to relax
waterfall

[Lance R. Casey]

From our current vocabulary:

although

Perhaps covered, at least partially, by mi yet, still.

faith/belief

tìspaw?

friendly

le'eylan?

Good morning (idiom)

It seems like there is no such thing.

I apologize/my apologies/I'm sorry (idiom)

Oe tsap'alute si

Perhaps just Tsap'alute! for short, to mirror Irayo! (irayo si).

See you later (colloquial good-bye idiom)

Is Kìyevame! too formal?

Superlative Construction

Tsole'a syetutet atsawl frato mì sìrey
We saw the biggest Trapper I've ever seen ("in [my] life")

to do

Kem si?

to like (someone or something)

At least so far, this has been handled with X a fì'u oeru prrte' lu.

to quiet

fneyku?

water

Suggested *pay extracted from plant names, but confirmation is needed since we know that elision often occurs in compounds.

wise

txantslusam wise ("much-knowing")

*If tìrol is "song" what's "singing" (as a gerund/noun)

tìrusol (cf. Koren a'awve tìruseyä 'awsiteng The first rule of living together)

mine/yours/his/hers/ours/theirs

At least in predicative situations, the bare genitive seem to work:

Fìtsenge... awngeyä!
This... this is our land!

to dream

Unil si?

to relax

tsurokx rest

[Is.]

Good ones here. I was also wondering about darkness, as the opposite of atan, light. Leaf is also a noun I'd like, especially as we got all the other tree parts! Tangek, tree-trunk. Vul, branch.

I would also like to suggest we try to get a word for: difficult, tough, hard, complex. The opposite of ftue, easy, that is. Oeru lì'fyati leNa'vi [difficult?] nerume! Learning the Na'vi language is difficult for me! (I presume you don't need to throw in a "lu" there, right?)

[NeotrekkerZ]

Thanks, I personally wanted leaf for the Firefly reference. 

I don't think although could be achieved with mi.  Consider "Although you gave me X I still want Y.

A few more for the list:
kind
generous
very (yes we have fìtxan, but that implies excessive; I just want "very adj")
around (preposition)
curious/curiosity
anxious/anxiety/nervous
without (preposition)
of course!/naturally! (idiom)

Weather (clouds, cloudy, lightning, etc)

[Prrton]

Good ones here. I was also wondering about darkness, as the opposite of atan, light. Leaf is also a noun I'd like, especially as we got all the other tree parts! Tangek, tree-trunk. Vul, branch.

I would also like to suggest we try to get a word for: difficult, tough, hard, complex. The opposite of ftue, easy, that is. Oeru lì'fyati leNa'vi [difficult?] nerume! Learning the Na'vi language is difficult for me! (I presume you don't need to throw in a "lu" there, right?)

The "find the opposite" approach is a very good one. I'd suggest that that's a good way for all of the nouns/verbs/adjectives to be devised in format as well. There are already many cases in which we have HALF of a pair already. I believe that pairing them up is helpful not only in coming up with more, but perhaps even for K Pawl in fleshing them out. He can decide. We just have to be prepared for some of the pairs that come back to be [SOMETHING]/"NOT"-[SOMETHING] as opposed to [SOMETHING]/[SOMETHING's OPPOSITE]. Many languages do this. Esperanto does it A LOT with "mal-".

[Nawmaritie]

Good ones here. I was also wondering about darkness, as the opposite of atan, light. Leaf is also a noun I'd like, especially as we got all the other tree parts! Tangek, tree-trunk. Vul, branch.

I would also like to suggest we try to get a word for: difficult, tough, hard, complex. The opposite of ftue, easy, that is. Oeru lì'fyati leNa'vi [difficult?] nerume! Learning the Na'vi language is difficult for me! (I presume you don't need to throw in a "lu" there, right?)

The "find the opposite" approach is a very good one. I'd suggest that that's a good way for all of the nouns/verbs/adjectives to be devised in format as well. There are already many cases in which we have HALF of a pair already. I believe that pairing them up is helpful not only in coming up with more, but perhaps even for K Pawl in fleshing them out. He can decide. We just have to be prepared for some of the pairs that come back to be [SOMETHING]/"NOT"-[SOMETHING] as opposed to [SOMETHING]/[SOMETHING's OPPOSITE]. Many languages do this. Esperanto does it A LOT with "mal-".

I think it would be kinda nice to have an "opposite marker/affix" then, instead of "NOT"-[SOMETHING], because for a lot of (most ?) words it's not the opposite if one just says "not-something". e.g. "hot", "not hot" doesn't make it "cold", but more like "meh, it's warm, but not hot". With an "opposite" marker it would work:
"hot" -> "not hot" -> "not [opposite]hot" -> "[opposite]hot"
With a word like "easy" it's different though, but that may be from how that word works in German (bit I think it's the same in English), because "not easy" sounds more difficult than "not difficult", but that doesn't mean it has to work that way in Na'vi

[Kì'eyawn]

Thanks, I personally wanted leaf for the Firefly reference. 

I don't think although could be achieved with mi.  Consider "Although you gave me X I still want Y.

A few more for the list:
kind
generous
very (yes we have fìtxan, but that implies excessive; I just want "very adj")
around (preposition)
curious/curiosity
anxious/anxiety/nervous
without (preposition)
of course!/naturally! (idiom)

Weather (clouds, cloudy, lightning, etc)

Love for the Firefly/Serenity reference

and i would add to your list:

gentle
cruel/mean

[NeotrekkerZ]

I think it would be kinda nice to have an "opposite marker/affix" then, instead of "NOT"-[SOMETHING], because for a lot of (most ?) words it's not the opposite if one just says "not-something". e.g. "hot", "not hot" doesn't make it "cold", but more like "meh, it's warm, but not hot".

An affix would be good, but potentially the coolest part of this whole scenario, at least for me, is that we get some different words as well with sound combinations that we haven't heard before or have only 1 or 2 examples of.  You're quote got me thinking about the following:

cool/warm (as temperature)
cool (as in neat, awesome, na'vi slang)
fortune
good luck/may fortune smile upon you (idiom)

[Lance R. Casey]

good luck/may fortune smile upon you (idiom)

Given here -- and yes, it includes "smile".

[NeotrekkerZ]

Thanks for that!

['eylan na'viyä]

I think it would be kinda nice to have an "opposite marker/affix" then, instead of "NOT"-[SOMETHING], because for a lot of (most ?) words it's not the opposite if one just says "not-something". e.g. "hot", "not hot" doesn't make it "cold", but more like "meh, it's warm, but not hot".

An affix would be good, but potentially the coolest part of this whole scenario, at least for me, is that we get some different words as well with sound combinations that we haven't heard before or have only 1 or 2 examples of.  You're quote got me thinking about the following:

cool/warm (as temperature)
cool (as in neat, awesome, na'vi slang)
fortune
good luck/may fortune smile upon you (idiom)

here are some thoughts about good luck/fortune:
http://forum.learnnavi.org/vocabulary-expansion/non-english-concepts/