Crossword clues for the word: NIXIE The word NIXIE has appeared as an answer to at least 12 crossword clues on different crossword puzzles. Crossword clues for NIXIE Showing 1 to 12 of 12 results Clue(s) "Dead letter, in post office talk" "Undeliverable letter, in post-office slang" "Undeliverable letter, in post-office talk" "Undeliverable letter, to a postal worker" "Undeliverable letter, to postal employees" Dungeon & Dragons creature Female sprite Germanic water spirit Germanic water sprite Undeliverable letter Undeliverable piece of mail Undeliverable piece of mail: Slang.