How many letters does the top answer for “lacking distinct or individual characteristics; dull and uninteresting” have?

The most common answer is characterless (13 letters).

Crossword clue: lacking distinct or individual characteristics; dull and uninteresting

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

characterless 13 letters wn-def

lacking distinct or individual characteristics; dull and uninteresting

nondescript 11 letters wn-def

a person is not easily classified and not very interesting