Kept cool (8)
I believe this is a double definition.
'kept' is the first definition.
(to keep is to reserve or hold onto)
'cool' is the second definition.
(similar in meaning)
(Other definitions for reserved that I've seen before include "Set aside; reticent" , "Retiring" , "Held back, set aside" , "without emotion" , "unforthcoming" .)
'kept' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'cool' is the wordplay.
I cannot quite understand how this works, but
'cool' could be 'ice' (icing is a kind of cooling) and 'ice' is found in the answer.
The remaining letters 'on' 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 on ice that I've seen before include "Predatory insect" , "kept for later" , "Ready to skate" , "In store, preserved" , "Shelved" .)