confine vs pin down

confine and pin down both are verbs.

Word	Noun	Adjective	Verb	Adverb
confine	No	No	Yes	No
pin down	No	No	Yes	No

As verbs, pin down is a hyponym of confine; that is, pin down is a word with a more specific, narrower meaning than confine:

confine (verb)	pin down (verb)
place limits on (extent or amount or access)	define clearly
to close within bounds, or otherwise limit or deprive of free movement	attach with or as if with a pin
prevent from leaving or from being removed	place in a confining or embarrassing position
deprive of freedom; take into confinement
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