Meaning of “pin” - Learner’s Dictionary

pin

verb [ T ] uk us /pɪn/ (present participle pinning, past tense and past participle pinned)

B1 to fasten something with a pin:

We're not allowed to pin anything on these walls.
She had a red ribbon pinned to her collar.
pin sb to/against/under, etc

to force someone to stay in a position by holding them:

They pinned him to the ground.
→ See also pin your hopes on sb/sth

(Definition of “pin verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)