air bag vs constraint

air bag and constraint both are nouns.

Word	Noun	Adjective	Verb	Adverb
air bag	Yes	No	No	No
constraint	Yes	No	No	No

As nouns, constraint is a hypernym of air bag; that is, constraint is a word with a broader meaning than air bag:

air bag: a safety restraint in an automobile; the bag inflates on collision and prevents the driver or passenger from being thrown forward
constraint: a device that retards something's motion

Other hypernyms of air bag include bag, restraint.

air bag (noun)	constraint (noun)
a safety restraint in an automobile; the bag inflates on collision and prevents the driver or passenger from being thrown forward	the act of constraining; the threat or use of force to control the thoughts or behavior of others
	a device that retards something's motion
	the state of being physically constrained