Bit of a yen (3)
I believe the answer is:
sen
'bit of a yen' is the definition.
('sen' is part of 'yen')
This is the entire clue.
(Other definitions for sen that I've seen before include "nurse" , "Fraction of yen" , "One hundredth of a rupiah" , "Formerly one hundredth of a yen" , "Japanese coin" .)