How many letters does the top answer for “see water brash, under brash.” have?

The most common answer is pyrosis (7 letters).

Crossword clue: see water brash, under brash.

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

pyrosis 7 letters web-def

a painful burning sensation in the chest caused by gastroesophageal reflux (backflow from the stomach irritating the eso

see water buck, under 3d buck. 50% similar → leche