to make hair look tidy using a comb:
Melanie ran upstairs to comb her hair.
to search a place thoroughly
comb something for somebody/something
Police are still combing the woods for the missing boy.
comb something ↔ outphrasal verb
to use a comb to make untidy hair look smooth and tidy:
She sat combing out her hair in front of the kitchen mirror.
comb through somethingphrasal verb
We spent weeks combing through huge piles of old documents.