It's just too good for the golfing Colonel (3)
I believe the answer is:
par
'colonel' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for par that I've seen before include "Rap to get even" , "Rating of strokes required for hole (golf)" , "Average or even, as for the course" , "What is normal - . . . for the course" , "normal amount" .)