foothold vs airhead

foothold and airhead both are nouns.

Word	Noun	Adjective	Verb	Adverb
foothold	Yes	No	No	No
airhead	Yes	No	No	No

As nouns, airhead is a hyponym of foothold; that is, airhead is a word with a more specific, narrower meaning than foothold:

foothold: an area in hostile territory that has been captured and is held awaiting further troops and supplies
airhead: a bridgehead seized by airborne troops

Other hyponyms of foothold include beachhead.

foothold (noun)	airhead (noun)
an initial accomplishment that opens the way for further developments	a bridgehead seized by airborne troops
a place providing support for the foot in standing or climbing	a flighty scatterbrained simpleton
an area in hostile territory that has been captured and is held awaiting further troops and supplies