13 possible answers to
Answers with 5 characters: ASKER MODEL Answers with 6 characters: ENIGMA RIDDLE Answers with 9 characters: CONUNDRUM HYPOCRITE MANNEQUIN Answers with 11 characters: BRAINTEASER GORDIANKNOT Answers with 12 characters: JIGSAWPUZZLE MYSTERYNOVEL Answers with 13 characters: SECRETAGENT-2 Answers with 15 characters: TOUGHNUTTOCRACK