Copy its head - friend captures it (7)
I believe the answer is:
imitate
'copy' is the definition.
(I know that copy can be written as imitate)
'its head friend captures it' is the wordplay.
'head' says to take the initial letters.
'friend' becomes 'mate' (mate is a kind of friend).
'captures' indicates putting letters inside.
The initial letter of 'its' is 'i'.
'mate' going around 'it' is 'mitate'.
'i'+'mitate'='IMITATE'
(Other definitions for imitate that I've seen before include "Take as a model" , "Copy or mimic" , "Mimic or follow as a model" , "'Ape, copy (7)'" , "Appear like, in behaviour or appearance" .)