6
demonstrable(adjective, clear, true, real, valid)
6
doubtless(adjective, adverb, clear, definite, sure)
6
faithful(adjective, good, strong, correct, honest)
6
foolproof(adjective, flawless, faultless, textbook, infallible)
6
given(determined, distinctive, assumed)
6
honest(adjective, clear, strong, flat, total)
6
marked(adjective, close, superior, unusual, exceptional)
6
right(adjective, correct, perfect, exact, physical)
6
sanguine(adjective, strong, easy, firm, solid)
6
self-confident(adjective, strong, easy, firm, solid)
6
single(adjective, alone, isolation, apart)
6
solid(adjective, good, strong, sound, correct)
6
stable(adjective, good, strong, easy, firm)
6
sundry(adjective, referring)
6
ultimate(adjective, ideal, all time, the best)
6
valid(adjective, correct, honest, true, straight)
6
various(adjective, referring)
6
veracious(adjective, good, strong, solid, true)
5
affirmative(adjective, clear, sure, affirmation, affirmative)
5
certified(adjective, honest, true, straight, definite)
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APASmart Define. (2016). certain thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/certain/thesaurus/synonyms
ChicagoSmart Define. 2016. "certain thesaurus" https://smartdefine.org/certain/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2016, certain thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/certain/thesaurus/synonyms>.
MLASmart Define. "certain thesaurus" 31 March 2016. Web. 20 September 2026. <https://smartdefine.org/certain/thesaurus/synonyms>