Collocations for fingernail - noun

long
sharp
black, dirty
broken
manicured
painted, red

clip (esp. AmE), cut
paint
bite, chew
break
dig in
She dug her fingernails into my neck.

run
tap
She tapped her fingernails against the table impatiently.

examine, inspect
‘Actually, I'm leaving,’ she said, examining her fingernails.

dig in
scrape
the horrible sound of fingernails scraping across a blackboard

grow

polish (esp. AmE)
clippers

under the/your fingernails
I noticed I had dirt under my fingernails.