What do these words mean?

[Neytiri Na'Vi]

What does "tswivayon" mean? And what does "livu" mean?

[wm.annis]

What does "tswivayon" mean? And what does "livu" mean?

These are verbs which have the subjunctive infix (Na'vi doesn't just have prefixes and suffixes, but infixes — they go into the middle of a word in various fixed locations).  We use angles around infixes, so your words are:

tsw‹iv›ayon, the verb tswayon "to fly"
l‹iv›u, the verb lu "to be"

[Neytiri Na'Vi]

AWSOME! Irayo!!!