used to make fun of something that is defenitly NOT funny.
Saying it more then once (ex: FOONAH! FOONAH!) increases the level of sarcasm.
Also, if you put tres in front of it, (ex: that was tres foonah) you can go to a level of foonah, never reached before. But, you must say tres very quietly, to keep it on th DL.
Foon is a shortening of foonah in case you are to lazy to say the real word.
me: FOONAH! FOONAH!
2. Me: that was *whisper* tres *stops whisper* foonah!