vest pocket vs fob

vest pocket and fob both are nouns.

Word	Noun	Adjective	Verb	Adverb
vest pocket	Yes	No	No	No
fob	Yes	No	Yes	No

As nouns, fob is a hyponym of vest pocket; that is, fob is a word with a more specific, narrower meaning than vest pocket:

Other hyponyms of vest pocket include watch pocket.

vest pocket (noun)	fob (noun)
a small pocket in a man's vest	short chain or ribbon attaching a pocket watch to a man's vest
	an adornment that hangs from a watch chain
	a vest pocket to hold a pocket watch

vest pocket (verb)	fob (verb)
	deceive somebody