Bound to field fourth complaint (4)
I believe the answer is:
leap
'bound' is the definition.
(I know that bound can be written as leap)
'field fourth complaint' is the wordplay.
'field' becomes 'lea' (lea can mean a meadow or field of grass).
'fourth complaint' becomes 'p' (4th letter of 'complaint').
'lea'+'p'='LEAP'
'to' acts as a link.
(Other definitions for leap that I've seen before include "as 1984 was" , "'Look before you . . . .'" , "Basket" , "Spring suddenly" , "Abrupt change; spring" .)