bushing vs insulator

bushing and insulator both are nouns.

Word	Noun	Adjective	Verb	Adverb
bushing	Yes	No	No	No
insulator	Yes	No	No	No

As nouns, insulator is a hypernym of bushing; that is, insulator is a word with a broader meaning than bushing:

bushing: an insulating liner in an opening through which conductors pass
insulator: a material such as glass or porcelain with negligible electrical or thermal conductivity

Other hypernyms of bushing include dielectric, nonconductor.

bushing (noun)	insulator (noun)
a cylindrical metal lining used to reduce friction	a material such as glass or porcelain with negligible electrical or thermal conductivity
an insulating liner in an opening through which conductors pass