Wise Sanders has blown his top (5)
I believe the answer is:
ernie
'wise' is the definition.
(comedian Ernie Wise)
'sanders has blown his top' is the wordplay.
'sanders' becomes 'Bernie' (US senator Bernie Sanders).
'has blown his top' means to remove the first letter (the letter at the top is removed).
'bernie' with its first letter taken away is 'ERNIE'.
(Other definitions for ernie that I've seen before include "Premium Bond selecting machine" , "- - Bevin, 13 dn" , "It picks Premium Bond winners" , "Wise for instance" , "Male" .)