Animal runs in circle round Henry (5)
I believe the answer is:
rhino
'animal' is the definition.
(I've seen this before)
'runs in circle round henry' is the wordplay.
'runs in' becomes 'rin' (I am not sure about this - if you are sure you should believe this answer much more).
'circle' becomes 'o'.
'round' is an insertion indicator.
'henry' becomes 'h' ('H' can be a synonym of 'henry').
'rin'+'o'='rino'
'rino' placed around 'h' is 'RHINO'.
Can you help me to learn more?
(Other definitions for rhino that I've seen before include "Cash" , "Stumpy" , "Beastly type that could charge you" , "In brief, large thick-skinned animal of Africa" , "Massive mammal with one or two horns on its nose, in short" .)