Collocations for trousers - noun

long, short (BrE)
I was still in short trousers (= still only a boy) at the time.

baggy, loose
tight
drainpipe (BrE), flared
camouflage, combat
pyjama/pajama, tracksuit (BrE)
corduroy, cotton, leather, linen

pair

pull on, pull up
He quickly pulled on his trousers and a T-shirt.

drop, pull down, unzip
He dropped his trousers in a rude gesture.

bottoms, leg, pocket
He tucked his trouser bottoms into his socks.

in trousers
He disapproves of women in trousers.