Calmly collected (4)
I believe the answer is:
cool
'collected' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for cool that I've seen before include "Not hot or warm - just unexcited" , "chic" , "Calm and unemotional" , "Unemotional; chill" , "Relaxed; not warm" .)