peg down vs pin down

peg down and pin down both are verbs.

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

As verbs, peg down and pin down are synonyms defined as:

Other synonyms of peg down include nail down, narrow, narrow down, specify.

peg down (verb)	pin down (verb)
define clearly	define clearly
fasten or secure with a wooden pin	attach with or as if with a pin
	place in a confining or embarrassing position