have a go vs seek

have a go is not a noun while seek is a noun.

Word	Noun	Adjective	Verb	Adverb
have a go	No	No	Yes	No
seek	Yes	No	Yes	No

As verbs, seek is a hypernym of have a go; that is, seek is a word with a broader meaning than have a go:

Other hypernyms of have a go include assay, attempt, essay, try.

have a go (noun)	seek (noun)
	the movement of a read/write head to a specific data track on a disk

have a go (verb)	seek (verb)
make an attempt at something	inquire for
	try to locate or discover, or try to establish the existence of
	go to or towards
	try to get or reach
	make an effort or attempt