ponytail vs coiffure

ponytail and coiffure both are nouns.

Word	Noun	Adjective	Verb	Adverb
ponytail	Yes	No	No	No
coiffure	Yes	No	Yes	No

As nouns, coiffure is a hypernym of ponytail; that is, coiffure is a word with a broader meaning than ponytail:

ponytail: a hair style that draws the hair back so that it hangs down in back of the head like a pony's tail
coiffure: the arrangement of the hair (especially a woman's hair)

Other hypernyms of ponytail include coif, hair style, hairdo, hairstyle.

ponytail (noun)	coiffure (noun)
a hair style that draws the hair back so that it hangs down in back of the head like a pony's tail	the arrangement of the hair (especially a woman's hair)

ponytail (verb)	coiffure (verb)
	arrange attractively