How many letters does the top answer for “act of cooperating traitorously with an enemy that is occupying your country” have?

The most common answer is collaborationism (16 letters).

Crossword clue: act of cooperating traitorously with an enemy that is occupying your country

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

collaborationism 16 letters wn-def

act of cooperating traitorously with an enemy that is occupying your country

quislingism 11 letters wn-def

act of cooperating traitorously with an enemy that is occupying your country