inflatable cushion vs air cushion

inflatable cushion and air cushion both are nouns.

Word	Noun	Adjective	Verb	Adverb
inflatable cushion	Yes	No	No	No
air cushion	Yes	No	No	No

As nouns, inflatable cushion and air cushion are synonyms defined as:

inflatable cushion and air cushion: a cushion usually made of rubber or plastic that can be inflated

inflatable cushion (noun)	air cushion (noun)
a cushion usually made of rubber or plastic that can be inflated	a cushion usually made of rubber or plastic that can be inflated
	a mechanical device using confined air to absorb the shock of motion
	the trapped air that supports a hovercraft a short distance above the water or ground