How many letters does the top answer for “the act of persisting or persevering; continuing or repeating behavior” have?

The most common answer is perseverance (12 letters).

Crossword clue: the act of persisting or persevering; continuing or repeating behavior

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

perseverance 12 letters wn-def

the act of persisting or persevering; continuing or repeating behavior

perseveration 13 letters wn-def

the act of persisting or persevering; continuing or repeating behavior