aˈssistful,a. ? Obs. [f. assist v. + -ful, prob. after helpful (which is f.helpn. + -ful).] Helpful. 1600Chapman Iliad v. 120 If ever in the cruel field thou hast assistful stood.1720Gibson Dispens. i. §2 (1734) 34 [Milk] sometimes proves very assistful in ripening Tumors.