expression, noun
difficult person; good-for-nothing; pain in the neck
Refers to a person who is troublesome, hard to deal with, or a nuisance. Often used in exasperation. The gloss 'pain in the ass' is vulgar; 'pain in the neck' is a milder equivalent.
彼は本当に困った人だ。
He's really a difficult person.
あの困った人には手を焼いている。
I'm at my wits' end with that good-for-nothing.
From the past tense of 困る (to be troubled) + 人 (person), literally 'a person who has become troubled' or 'a troubling person'.