gripe vs objection

gripe and objection both are nouns.

Word	Noun	Adjective	Verb	Adverb
gripe	Yes	No	Yes	No
objection	Yes	No	No	No

As nouns, objection is a hypernym of gripe; that is, objection is a word with a broader meaning than gripe:

gripe (noun)	objection (noun)
informal terms for objecting	(law) a procedure whereby a party to a suit says that a particular line of questioning or a particular witness or a piece of evidence or other matter is improper and should not be continued and asks the court to rule on its impropriety or illegality
	the act of protesting; a public (often organized) manifestation of dissent
	the speech act of objecting
	the act of expressing earnest opposition or protest

gripe (verb)	objection (verb)
complain