How many letters does the top answer for “causing cold; producing or generating cold. quincy.” have?

The most common answer is frigorific (10 letters).

Crossword clue: causing cold; producing or generating cold. quincy.

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

frigorific 10 letters web-def

causing cold; cooling or chilling

frigorifical 12 letters web-def

Causing cold; producing or generating cold. Quincy.