insulant vs lagging

insulant and lagging both are nouns.

Word	Noun	Adjective	Verb	Adverb
insulant	Yes	No	No	No
lagging	Yes	No	No	No

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

insulant: insulating material that reduces or prevents the transmission of heat or sound or electricity
lagging: insulation used to wrap around pipes or boilers or laid in attics to prevent loss of heat

Other hyponyms of insulant include corkboard.

insulant (noun)	lagging (noun)
insulating material that reduces or prevents the transmission of heat or sound or electricity	insulation used to wrap around pipes or boilers or laid in attics to prevent loss of heat