Slippery character handed over cash without hesitation (7)
I believe the answer is:
serpent
'slippery character' is the definition.
(slippery or slithering animal)
'handed over cash without hesitation' is the wordplay.
'handed over cash' becomes 'spent'.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'hesitation' becomes 'er' (sound used when hesitating).
'spent' going around 'er' is 'SERPENT'.
(Other definitions for serpent that I've seen before include "Fruit supplier" , "Present for a snake" , "Tempting" , "Scaly reptile" , "(In literature) a snake" .)