Contracts speeded up arguments (7)
I believe the answer is:
narrows
'contracts' is the definition.
('narrow' can be a synonym of 'contract')
'speeded up arguments' is the wordplay.
'speeded' becomes 'ran' (running is a kind of speeding).
'up' is a reversal indicator (in down clue: letters go upwards).
'arguments' becomes 'rows' (I've seen this before).
'ran' back-to-front is 'nar'.
'nar'+'rows'='NARROWS'
(Other definitions for narrows that I've seen before include "Confines" , "Constricts" , "Loses width" , "Confined channel" , "Gets less wide" .)