In cooler temperature, child is delivered (6)
I believe the answer is:
infant
'child is delivered' is the definition.
I can't tell whether this definition defines the answer.
'in cooler temperature' is the wordplay.
'cooler' becomes 'fan' (I've seen this before).
'temperature' becomes 't' (abbreviation).
'in'+'fan'+'t'='INFANT'
(Other definitions for infant that I've seen before include "Juvenile" , "Tot" , "Babe" , "Youngster" , "Very young child or baby" .)