hairpin vs hairgrip

hairpin and hairgrip both are nouns.

Word	Noun	Adjective	Verb	Adverb
hairpin	Yes	No	No	No
hairgrip	Yes	No	No	No

As nouns, hairgrip is a hyponym of hairpin; that is, hairgrip is a word with a more specific, narrower meaning than hairpin:

hairpin: a double pronged pin used to hold women's hair in place
hairgrip: a flat wire hairpin whose prongs press tightly together; used to hold bobbed hair in place

Other hyponyms of hairpin include bobby pin, grip, bodkin.

hairpin (noun)	hairgrip (noun)
a double pronged pin used to hold women's hair in place	a flat wire hairpin whose prongs press tightly together; used to hold bobbed hair in place