难看(nán kàn) - ugly, unsightly in Mandarin

难看 (nán kàn) is built exactly the way it looks: 难 (nán), "difficult", plus 看 (kàn), "to look at" - something "difficult to look at", hence ugly or unsightly. It is the straightforward opposite of 好看 (hǎo kàn), "good-looking", and the two form a pair every learner meets early.

难看 (nán kàn) covers more ground than English "ugly" tends to. It describes clothes, colours, handwriting, a badly decorated room, even an awkward result or a poor performance - anything unpleasant to look at or, by extension, to witness. 她的字写得有点难看 (tā de zì xiě de yǒudiǎn nán kàn), "her handwriting looks a bit ugly", is a perfectly ordinary, unremarkable comment.

Be careful using 难看 (nán kàn) about a person's face directly - it reads as blunt, even rude, in a way English "not good-looking" softens. Chinese speakers reach for it about objects and situations far more readily than about people.