How many letters does the top answer for “capable of being left out” have?

The most common answer is omissible (9 letters).

Crossword clue: capable of being left out

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

omissible 9 letters wn-def

capable of being left out

capable of being ascertained or found out 50% similar → ascertainable, discoverable

capable of being drawn out feltham. 50% similar → ductible

capable of being spit out. bailey. 50% similar → screable