How many letters does the top answer for “out of condition; not strong or robust; incapable of exertion or endurance” have?

The most common answer is flabby (6 letters).

Crossword clue: out of condition; not strong or robust; incapable of exertion or endurance

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

flabby 6 letters wn-def

out of condition; not strong or robust; incapable of exertion or endurance

flaccid 7 letters wn-def

out of condition; not strong or robust; incapable of exertion or endurance