Destiny affected mood (4)
I believe the answer is:
doom
'destiny' is the definition.
(I've seen this before)
'affected mood' is the wordplay.
'affected' indicates an anagram.
'mood' anagrammed gives 'DOOM'.
(Other definitions for doom that I've seen before include "Inevitable ruin" , "Inescapable fate" , "In the end" , "Mood of death or ruin" , "Sentence" .)