Peas, presumably, would not form part of it (6,4)
I believe the answer is:
square meal
'part of it' is the definition.
The definition suggests an adjective which matches the answer.
'peas presumably would not form' is the wordplay.
I cannot quite see how this works, but
'form' could be 'square' (squaring is a kind of forming) and 'square' is found within the answer.
The remaining letters 'meal' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for square meal that I've seen before include "Courses" , "Satisfying food" , "proper food" , "apparently not a round of sandwiches?" , "Substantial repast" .)