Chance one day to cut stress (8)
I believe the answer is:
accident
'chance' is the definition.
(I've seen this before)
'one day to cut stress' is the wordplay.
'one' becomes 'I' (Roman numeral).
'day' becomes 'd' (abbreviation for day).
'to cut' is an insertion indicator.
'stress' becomes 'accent' (synonyms).
'i'+'d'='id'
'id' going into 'accent' is 'ACCIDENT'.
(Other definitions for accident that I've seen before include "Prang" , "Eg, car crash" , "Mishap, misadventure" , "Unforseen misfortune" , "Chance occurrence." .)