Stop getting fed up in row (6)
I believe the answer is:
detain
'stop' is the definition.
(I've seen this before)
'fed up in row' is the wordplay.
'fed' becomes 'ate' ('eat' can be a synonym of 'feed').
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'in' indicates putting letters inside.
'row' becomes 'din' (both can mean a loud disturbance).
'ate' back-to-front is 'eta'.
'eta' going within 'din' is 'DETAIN'.
'getting' acts as a link.
(Other definitions for detain that I've seen before include "Ate din (anag.)" , "Keep back or arrest" , "Hold in custody or delay" , "Hold (someone) back" , "Stop" .)