ugly

an ugly duckling

someone or something that is ugly and not successful when they are young or new, but which develops into something beautiful and successful. The most successful company was last year's ugly duckling.

be as ugly as sin

to be very ugly. That dog of his is as ugly as sin.

See also: sin

raise/rear its (ugly) head

if something unpleasant raises its ugly head, it becomes a problem that people have to deal with. All over Europe, racism is rearing its ugly head once more.

See also: head, raise, rear