Synonyms of unforgetful

1 Syllable

set, firm, tough, sure, stout, staunch, bound, true, fast, tight

2 Syllables

clinging, stubborn, mulish, stalwart, steadfast, spunky, iron, solid, sturdy, dogged

3 Syllables

persistent, coherent, adamant, strong-willed, tenacious, unswerving, persisting, relentless, forceful

4 Syllables

possessive, intransigent, obdurate, unshakable, purposeful, resolute, cohesive, obstinate, retentive, inflexible, pertinacious, persevering, determined