How many letters does the top answer for “one who practices or advocates vivisection; a vivisector.” have?

The most common answer is vivisectionist (14 letters).

Crossword clue: one who practices or advocates vivisection; a vivisector.

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

vivisectionist 14 letters web-def

a biologist who cuts open live animals for research

one who advocates or practices nephalism. 50% similar → nephalist

one who advocates or practices opportunism. 50% similar → opportunist

one who advocates the practice of cremation. 50% similar → cremationist