Fruit cut up, a leftist thought (7)
I believe the answer is:
figured
'thought' is the definition.
(I've seen this before)
'fruit cut up a leftist' is the wordplay.
'fruit' becomes 'fig' (fig is a kind of fruit).
'cut' means to remove the last letter.
'a leftist' becomes 'red' (red can informally mean communist).
'up' with its final letter taken off is 'u'.
'fig'+'u'+'red'='FIGURED'
(Other definitions for figured that I've seen before include "Thought" , "Reckoned" .)