unresisting vs resistless

unresisting and resistless both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unresisting	No	Yes	No	No
resistless	No	Yes	No	No

As adjectives, unresisting and resistless are synonyms defined as:

unresisting and resistless: offering no resistance, passively accepting of a situation

unresisting (adjective)	resistless (adjective)
offering no resistance, passively accepting of a situation	impossible to resist; overpowering
	offering no resistance, passively accepting of a situation