Brown, following small defeat, initially has to suffer (5)
I believe the answer is:
stand
'to suffer' is the definition.
('stand' can be a synonym of 'suffer')
'brown following small defeat initially' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown).
'following' means one lot of letters go next to another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'initially' suggests taking the first letters.
The first letter of 'defeat' is 'd'.
'tan' after 's' is 'stan'.
'stan'+'d'='STAND'
'has' acts as a link.
(Other definitions for stand that I've seen before include "stick" , "Get to one's feet" , "principled position" , "Base < put up with" , "partnership" .)