1) Asker 2) Conundrum 3) Enigma 4) Gordian knot 5) Hypocrite 6) Jig-saw puzzle 7) Mannequin 8) Model 9) Mystery 10) Mystery novel 11) Poseur 12) Poseuse 13) Posturer 14) Puzzle 15) Question 16) Riddle 17) Secret agent 18) Stumper 1) Baffler 2) Baffling problem 3) Baffling puzzle 4) Baffling question 5) Basis of bafflement 6) Brain tickler 7) Brainteaser 8) Cheese sayer 9) Confusing query 10) Confusing question 11) Conundrum 12) Difficult problem 13) Difficult puzzle 14) Difficult question 15) Enigma 16) Exhibitionist 17) Hard one 
[Noun] A difficult or awkward matter to be dealt with.
Poser is a 3D computer graphics program optimized for 3D modeling of human figures. The program has gained popularity due to allowing beginners to produce basic animations and digital images, and the extensive availability of third-party digital models. == Overview == Poser is a 3D rendering software package for the posing, animating and rendering...
• (n.) One who, or that which, puzzles; a difficult or inexplicable question or fact.
Pos'er noun One who, or that which, puzzles; a difficult or inexplicable question or fact. Bacon. 
Poser is British slang for a show-off, a pseud.
[n] - a particularly difficult or baffling question or problem
stumper noun a particularly difficult or baffling question or problem
A person pretending to be something he or she is not.
One who pretends to be something one is not.