Heavy figure to excite briefly (7)
I believe the answer is:
onerous
'heavy' is the definition.
(similar in meaning)
'figure to excite briefly' is the wordplay.
'figure' becomes 'one' (a numerical figure).
'to excite' becomes 'rouse' (I've seen this before).
'briefly' means to remove the last letter.
'rouse' with its final letter removed is 'rous'.
'one'+'rous'='ONEROUS'
(Other definitions for onerous that I've seen before include "Involving a great deal of effort" , "Challenging" , "Difficult, troublesome" , "Oppressive, difficult to bear" , "weight" .)