Spirited, if returning about English pen (6)
I believe the answer is:
feisty
'spirited' is the definition.
(similar in meaning)
'if returning about english pen' is the wordplay.
'returning' shows that the letters should be reversed in order.
'about' is an insertion indicator.
'english' becomes 'E' (abbreviation).
'pen' becomes 'sty' (both can mean an animal enclosure).
'if' in reverse letter order is 'fi'.
'fi' going around 'e' is 'fei'.
'fei'+'sty'='FEISTY'
(Other definitions for feisty that I've seen before include "Lively; determined" , "In slang, aggressive or excitable" , "Spirited and lively" , "Spirited; quarrelsome" , "Plucky and spirited" .)