An obsessed person after exercise finds protein source (6)
I believe the answer is:
peanut
'protein source' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'an obsessed person after exercise' is the wordplay.
'an' becomes 'a'.
'obsessed person' becomes 'nut' (nut is a kind of person. I am not sure about the 'obsessed' bit.).
'after' means one lot of letters go next to another.
'exercise' becomes 'pe' (Physical Education).
'a'+'nut'='anut'
'anut' put after 'pe' is 'PEANUT'.
'finds' is the link.
Can you help me to learn more?
(Other definitions for peanut that I've seen before include "Something to eat" , "A monkey delicacy" , "little bit of food" , "grows in the ground" , "Singularly little money" .)