Get pumped up about female behind (7)
I believe the answer is:
reflate
'get pumped up' is the definition.
'about female behind' is the wordplay.
'about' becomes 're' (common abbreviation for 'with reference to').
'female' becomes 'f' (abbreviation).
'behind' becomes 'late'.
're'+'f'+'late'='REFLATE'
(Other definitions for reflate that I've seen before include "raise expenditure" , "Blow up" .)