fire-resisting vs fire-retardant

fire-resisting and fire-retardant both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fire-resisting	No	Yes	No	No
fire-retardant	No	Yes	No	No

As adjectives, fire-resisting and fire-retardant are synonyms defined as:

Other synonyms of fire-resisting include fire-resistant, fire-resistive.

fire-resisting (adjective)	fire-retardant (adjective)
difficult to burn	difficult to burn