helpmate vs partner

helpmate and partner both are nouns.

Word	Noun	Adjective	Verb	Adverb
helpmate	Yes	No	No	No
partner	Yes	No	Yes	No

As nouns, partner is a hypernym of helpmate; that is, partner is a word with a broader meaning than helpmate:

Other hypernyms of helpmate include better half, married person, mate, spouse.

helpmate (noun)	partner (noun)
a helpful partner	an associate in an activity or endeavor or sphere of common interest
	a person's partner in marriage
	a person who is a member of a partnership

helpmate (verb)	partner (verb)
	provide with a partner
	act as a partner