crab louse vs pubic louse

crab louse and pubic louse both are nouns.

Word	Noun	Adjective	Verb	Adverb
crab louse	Yes	No	No	No
pubic louse	Yes	No	No	No

As nouns, crab louse and pubic louse are synonyms defined as:

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

Other synonyms of crab louse include crab, Phthirius pubis.

crab louse (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