Crossword clues for the word: RULEOFTHUMP The word RULEOFTHUMP has appeared as an answer to at least 3 crossword clues on different crossword puzzles. Crossword clues for RULEOFTHUMP Showing 1 to 3 of 3 results Clue(s) Guideline for testing watermelon ripeness? Guideline for the Three Stooges? Truism about a heavy heartbeat?