Question that baffles model (5)
I believe the answer is:
poser
This clue could be a double definition.
'question' is the first definition.
(a poser is a difficult question)
'baffles model' is the second definition.
'poser' can be an answer for 'model' (synonyms). I am unsure of the 'baffles' bit.
'that' acts as a link.
Can you help me to learn more?
(Other definitions for poser that I've seen before include "Tricky question" , "Show-off" , "This person's affected" , "Difficult problem" , "Hard problem" .)