automatic vs side arm

automatic and side arm both are nouns.

Word	Noun	Adjective	Verb	Adverb
automatic	Yes	Yes	No	No
side arm	Yes	No	No	No

As nouns, side arm is a hypernym of automatic; that is, side arm is a word with a broader meaning than automatic:

automatic: a pistol that will keep firing until the ammunition is gone or the trigger is released
side arm: a firearm that is held and fired with one hand

Other hypernyms of automatic include automatic firearm, automatic gun, automatic weapon, handgun, pistol, shooting iron.

automatic (noun)	side arm (noun)
self-loading rifle capable of automatic fire	a firearm that is held and fired with one hand
a pistol that will keep firing until the ammunition is gone or the trigger is released

automatic (adjective)	side arm (adjective)
operating with minimal human intervention; independent of external control
without volition or conscious control
resembling the unthinking functioning of a machine