Small pony manoeuvred around old beagle (6)
I believe the answer is:
snoopy
'beagle' is the definition.
(I've seen this before)
'small pony manoeuvred around old' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'manoeuvred' indicates an anagram.
'around' means one lot of letters goes inside another.
'old' becomes 'o' (abbreviation as in OT - Old Testament).
'pony' anagrammed gives 'nopy'.
'nopy' enclosing 'o' is 'noopy'.
's'+'noopy'='SNOOPY'
(Other definitions for snoopy that I've seen before include "Prying, as in Peanuts" , "Curious" , "Charlie Brown's cartoon dog" , "Cartoon beagle" , "Brown dog's" .)