Exercise my back after golf (3)
I believe the answer is:
gym
'exercise' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'my back after golf' is the wordplay.
'back' says the letters should be written in reverse.
'after' means one lot of letters go next to another.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'my' reversed gives 'ym'.
'ym' after 'g' is 'GYM'.
Can you help me to learn more?
(Other definitions for gym that I've seen before include "Fitness centre" , "Fitness club" , "Training room" , "PE" , "Room for exercising" .)