Unsuitable
Inappropriate
noun, な adjective
Something that is not suitable is unsuitable and inappropriate.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
人には適不適がある。
Everyone has things they are suited or unsuited for.
いい意味で、この仕事は君には不適だと思うよ。
In a positive sense, I think this job is unsuitable for you.
あまりにも受け身すぎる人は、結婚相手には不適です。
Someone who is too passive is not suitable as a marriage partner.
この職が私にとって適不適かを考えているんですが、まだ答えは出ていません。
I've been thinking about whether this job suits me or not, but I haven't found the answer yet.