Crossword clues for the word: FIRTHS The word FIRTHS has appeared as an answer to at least 5 crossword clues on different crossword puzzles. Crossword clues for FIRTHS Showing 1 to 5 of 5 results Clue(s) "Clyde, Forth and others" "Long, narrow estuaries" Actor Colin's kin Narrow arms of the sea Scottish estuaries