shortest

primarily temporal sense; indicating or being or seeming to be limited in duration;
(primarily spatial sense) having little length or lacking in length;
low in stature; not tall;
not sufficient to meet a need;
(of memory) deficient in retentiveness or range;
not holding securities or commodities that one sells in expectation of a fall in prices;
of speech sounds or syllables of relatively short duration;
less than the correct or legal or full amount often deliberately so;
lacking foresight or scope;
tending to crumble or break into flakes due to a large amount of shortening;
marked by rude or peremptory shortness;

shortest is a valid Scrabble (US) TWL word

shortest is a valid Scrabble Word in Merriam-Webster MW Dictionary

shortest is a valid Scrabble Word in International Collins CSW Dictionary

shortest is a valid Words With Friends word