Phthirius pubis vs pubic louse

Phthirius pubis and pubic louse both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phthirius pubis	Yes	No	No	No
pubic louse	Yes	No	No	No

As nouns, Phthirius pubis and pubic louse are synonyms defined as:

Phthirius pubis and pubic louse: a louse that infests the pubic region of the human body

Other synonyms of Phthirius pubis include crab, crab louse.

Phthirius pubis (noun)	pubic louse (noun)
a louse that infests the pubic region of the human body	a louse that infests the pubic region of the human body