One's frame of mind is reversed by fate (4)
I believe the answer is:
mood
'one's frame' is the definition.
'mood' can be an answer for 'frame' (I have seen 'Frame of mind ' mean 'mood' so perhaps 'frame' could also mean 'mood'). I'm not certain of the 'one's' bit.
'of mind is reversed by fate' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is located in the answer.
The remaining letters 'mod' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for mood that I've seen before include "An atmosphere of doom" , "sullenness may be indicative" , "melancholy" , "State of mind, humour" , "Low spirits" .)