What remains of one’s equilibrium (7)
I believe the answer is:
balance
'equilibrium' is the definition.
('balance' can be a synonym of 'equilibrium')
'what remains of one's' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (I've seen this in other clues) and 'an' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for balance that I've seen before include "Rest" , "emotional stability" , "Libra - amount in account" , "Sign" , "Weighing device" .)