Despicable man squashes grand philosopher (5)
I believe the answer is:
hegel
'philosopher' is the definition.
(Hegel is an example)
'despicable man squashes grand' is the wordplay.
'despicable man' becomes 'heel'.
'squashes' is an insertion indicator (some letters are squashed into a word).
'grand' becomes 'g' ('G' can be a synonym of 'grand').
'heel' going around 'g' is 'HEGEL'.
(Other definitions for hegel that I've seen before include "German philosopher, d. 1831" , "German 'dialectic' philosopher" , "Georg Wilhelm ---, Ger. philosopher" .)