How many letters does the top answer for “increase the pressure on a gas or liquid” have?

The most common answer is supercharge (11 letters).

Crossword clue: increase the pressure on a gas or liquid

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

supercharge 11 letters wn-def

increase the pressure on a gas or liquid

increase the pressure in or of 50% similar → pressurise, pressurize