Fetching details from the dictionary...

disliking; not wanting; unwilling (to do); reluctant
unpleasant; disagreeable; nasty; horrible; disgusting; undesirable; unwelcome
no!; quit it!; stop!
いやなことは忘れよう。
Let's forget unpleasant things.
この匂いはちょっと嫌だ。
This smell is kind of unpleasant.
いやだと言えなかった。
I couldn't say no.