ya~

hi!

yabu~

thicket

yaiba~

sword blade

yamette/yamero~

stop (as in when someone's about to do something, and you want them to quit)

yami~

darkness

yanagi~

willow

yarou~

bastard, idiot (basically on the lines of insult)

yasai~

vegetable(s)

yasashisa~

kindness/gentleness

yo~

This particle itself, added to the end of a phrase (Chotto yo!), adds emphasis, like an exclamation point. It can also be used as a greeting ("Yo - hisashiburi!")

yoika (?)~

listen

yogan~

lava

youkai~

general term for a supernatural being; usually used for demons

youki (or you-ki)~

demon's spiritual energy

yoma~

demon, monster [I'm pretty sure it's that meaning…]

Yomatsu Hara-Sakai~

Lands of the Night.

yorishiku (onegai shimasu)~

'be good to me' (said when introduced to someone, almost literally translated as this, but, in context, means 'Nice to meet you.')

yoru~

night

yosh(i)~

alright, okay

yoso~

element

yugami

distortion, warp

yugata~

evening

yuiitsu~

unique

yuki~

snow

yuko(na)~

valid

yuri~

lily

yurusenai~

I won't forgive this/you!

yuryoku(na)~

influential

yuuki~

courage (Miaka's last name! She's a charcter from Fushigi Yuugi, an anime…)

yuzurimasu/yuzuru/yuzutte~

yield (gives in/up)