pin2 past tense and past participle pinned, present participle pinning [transitive always + adverb/preposition]
to fasten something somewhere, or to join two things together, using a pin
pin something to/on something
Can you pin this to the notice board?
He pinned the name tag on his jacket.
pin something up
She had photos of her kids pinned up next to her desk.
to make someone unable to move by putting a lot of pressure or weight on them
pin somebody/something to something
He pinned her arms to her sides.
pin somebody against something
Albert got him pinned against the wall.
pin somebody down
They managed to pin him down until the police arrived.
be pinned under/beneath something
Her body was pinned under the weight of the car.
pin somebody/something ↔ downphrasal verb
to make someone give clear details or make a definite decision about something
pin somebody/something ↔ down to
Did you manage to pin him down to a definite date?
He's impossible to pin down.
to understand something clearly or be able to describe it exactly
hard/difficult to pin down
The flavour was hard to pin down.
if soldiers etc involved in fighting are pinned down, they cannot move from their position because someone is shooting at them:
The rebels have been pinned down in a camp to the south of the river.
pin something on somebody/somethingphrasal verb
to blame someone for something, often unfairly:
Don't try to pin the blame on me!
They're trying to pin the murder on the boyfriend.
to hope that something will happen or someone will help you, because all your plans depend on this:
Chris is pinning his hopes on getting into Yale.