Wild creature that is about (5)
I believe the answer is:
irate
'wild' is the definition.
(I've seen this before)
'creature that is about' is the wordplay.
'creature' becomes 'rat' (rat is a kind of creature).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'about' is an insertion indicator.
'rat' inserted inside 'ie' is 'IRATE'.
(Other definitions for irate that I've seen before include "Extremely angry" , "ranting" , "Annoyed, irritated" , "Spitting feathers" , "Wrathful" .)