Reasonable trade show (4)
I believe the answer is:
fair
I believe this clue is a double definition.
'reasonable' is the first definition.
('fair' can be a synonym of 'reasonable')
'trade show' is the second definition.
(I've seen this before)
(Other definitions for fair that I've seen before include "not cloudy" , "Free from discrimination" , "Just; passable" , "nothing special" , "Where the helter-skelter may be" .)