How many letters does the top answer for “not fit for sale” have?

The most common answer is unmerchantable (14 letters).

Crossword clue: not fit for sale

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

unmerchantable 14 letters wn-def

not fit for sale

fit to be offered for sale 50% similar → merchantable, sellable, vendable

not fit for habitation 50% similar → uninhabitable

not fit or appropriate. 50% similar → impair