Synonym word of unforgetful:

adamant, bound, clinging, coherent, cohesive, determined, dogged, fast, firm, forceful, inflexible, intransigent, iron, meaning business, mulish, obdurate, obstinate, persevering, persistent, persisting, pertinacious, possessive, purposeful, relentless, resolute, retentive, set, solid, spunky, stalwart, staunch, steadfast, stout, strong-willed, stubborn, sturdy, sure, tight, tough, true, unforgetful, unshakable, unswerving