The Irish one, perhaps, posing a puzzle? (6)
I believe the answer is:
setter
'puzzle?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for setter that I've seen before include "Crossword maker; dog" , "Hunting dog" , "Puzzle creator" , "Dog trained to point at game" , "I may pose a problem" .)