How many letters does the top answer for “having the power to increase perspiration.” have?

The most common answer is diaphoretic (11 letters).

Crossword clue: having the power to increase perspiration.

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

diaphoretic 11 letters web-def

used to produce perspiration

diaphoretical 13 letters web-def

Having the power to increase perspiration.

perspiration, or an increase of perspiration. 50% similar → diaphoresis