How many letters does the top answer for “being or having an unknown or unnamed source” have?

The most common answer is nameless (8 letters).

Crossword clue: being or having an unknown or unnamed source

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

nameless 8 letters wn-def

being or having an unknown or unnamed source

unidentified 12 letters wn-def

being or having an unknown or unnamed source