bad point

苦手(にがて)	2 meanings. 1) something I am poor at doing, 2) something I dislike. My 苦手 is rave music.

欠点(けってん)	Shortcoming. Opposite of 長所（ちょうしょ）. Can be used about people (he drinks too much, she always lies) or machines (this PC is very slow and prone to crashing). PPP TTT

弱点(じゃくてん)	Achilles heel, soft underbelly. A weakness that – while not correctable – is not a deal-breaker either. PPP TTT

欠陥(けっかん)	Defective. Have to take it back to the store. TTT