Pixie lover's sent up a bit (7)
I believe the answer is:
snaffle
'a bit' is the definition.
(type of bit used in horseriding)
'pixie lover's sent up' is the wordplay.
'pixie' becomes 'elf' (synonyms).
'lover's' becomes 'fan's' ('fan' can be a synonym of 'lover').
'sent up' is a reversal indicator.
'elf'+'fans'='elffans'
'elffans' back-to-front is 'SNAFFLE'.
(Other definitions for snaffle that I've seen before include "Kind of bit - take without permission" , "Horse's bit" , "A bit; to grab for oneself" , "Pinch" , "Illicitly take" .)