axilla vs armpit

axilla and armpit both are nouns.

Word	Noun	Adjective	Verb	Adverb
axilla	Yes	No	No	No
armpit	Yes	No	No	No

As nouns, axilla and armpit are synonyms defined as:

axilla and armpit: the hollow under the arm where it is joined to the shoulder

Other synonyms of axilla include axillary cavity, axillary fossa.

axilla (noun)	armpit (noun)
the hollow under the arm where it is joined to the shoulder	the hollow under the arm where it is joined to the shoulder