collocate vs group

collocate is not a noun while group is a noun.

Word	Noun	Adjective	Verb	Adverb
collocate	No	No	Yes	No
group	Yes	No	Yes	No

As verbs, group is a hypernym of collocate; that is, group is a word with a broader meaning than collocate:

collocate (noun)	group (noun)
	any number of entities (members) considered as a unit
	a set that is closed, associative, has an identity element and every element has an inverse
	(chemistry) two or more atoms bound together as a single unit and forming part of a molecule

collocate (verb)	group (verb)
group or chunk together in a certain order or place side by side	arrange into a group or groups
have a strong tendency to occur side by side	form a group or group together