try vs have a go

try is a noun but have a go is not a noun.

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

As verbs, have a go is a hyponym of try; that is, have a go is a word with a more specific, narrower meaning than try:

try (noun)	have a go (noun)
earnest and conscientious activity intended to do or accomplish something

try (verb)	have a go (verb)
put on a garment in order to see whether it fits and looks nice	make an attempt at something
melt (fat or lard) in order to separate out impurities
take a sample of
test the limits of
give pain or trouble to
make an effort or attempt
put to the test, as for its quality, or give experimental use to
examine or hear (evidence or a case) by judicial process
put on trial or hear a case and sit as the judge at the trial of