One of those high spirits (5)
I believe the answer is:
angel
'high spirits' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'one of those' is the wordplay.
I cannot really understand how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is found within the answer.
The remaining letters 'gel' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for angel that I've seen before include "darling!" , "somewhere in Islington" , "one might be recording" , "Winged spiritual being" , "Theatre backer" .)