pin down vs attach

pin down and attach both are verbs.

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

As verbs, attach is a hypernym of pin down; that is, attach is a word with a broader meaning than pin down:

pin down (verb)	attach (verb)
define clearly	become attached
attach with or as if with a pin	cause to be attached
place in a confining or embarrassing position	be attached; be in contact with
	take temporary possession of as a security, by legal authority
	create social or emotional ties