I am adult fly perhaps (5)
I believe the answer is:
imago
'i am adult fly perhaps' is the definition.
I can't judge whether this definition defines the answer.
'i am adult fly perhaps' is the wordplay.
'i am' becomes 'im'.
'adult' becomes 'a' (abbreviation).
'fly perhaps' becomes 'go' (fly can mean to leave or run away).
'im'+'a'+'go'='IMAGO'
(Other definitions for imago that I've seen before include "Maybe comma" , "Fully developed insect" , "That's as far as a butterfly can go" , "Perhaps butterfly" , "Beetle, for example" .)