Curtailment of complicated dispute to distress (6)
I believe the answer is:
harrow
'distress' is the definition.
(something harrowing is distressing)
'curtailment of complicated dispute' is the wordplay.
'curtailment of' means to remove the last letter (to curtail is to cut short).
'complicated' becomes 'hard' (I've seen this before).
'dispute' becomes 'row' (row is a kind of dispute).
'hard' with its final letter removed is 'har'.
'har'+'row'='HARROW'
'to' acts as a link.
(Other definitions for harrow that I've seen before include "Agricultural device" , "Clod breaker" , "It breaks up clods and covers seeds" , "Cultivator that pulverizes or smooths soil" , "A school; agricultural implement" .)