Peso fraction (7)
I believe the answer is:
centavo
'peso fraction' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for centavo that I've seen before include "Small coin of Mexico, Brazil, etc" , "(Of games) alternately on one's ground and an opponent's" , "bit of money" , "Mexican coin" , "Foreign money" .)