Fairly big orderly (4)
I believe the answer is:
tidy
I believe this clue is a double definition.
'fairly big' is the first definition.
(I've seen this before)
'orderly' is the second definition.
(associated in meaning)
(Other definitions for tidy that I've seen before include "Receptacle for odds and ends" , "Neat, ordered" , "generous" , "Set in order" , "Well-groomed" .)