Crossword Genius

Kept cool (8)

Ross

I believe the answer is:

This clue is a double definition.

'kept' is the first definition.
(reserving is a kind of keeping)

'cool' is the second definition.
(I've seen this before)

(Other definitions for reserved that I've seen before include "Unemotional; put by", "Bashful", "Retiring", "Slow to reveal emotion", "Set aside; reticent".)

I've seen this clue in The Telegraph.