IPA: //ʌnˈtruːɪst//
KK: /ʌnˈtruːɪst/
The most false or incorrect; not true at all.
His statement was the untruest of all the claims made during the debate.
Comparative: more untrue
Superlative: untruest
Untruest → It is formed from "un-" (meaning not) and "true" (from Old English "triewe", meaning faithful or loyal) and the superlative suffix "-est" (indicating the highest degree). The word "untruest" means the most untrue or the least faithful.
Think of 'not' ('un-') combined with 'faithful' ('true') to remember that 'untruest' means the most unfaithful or least true.