A kid with a chilled-out demeanour (2,4)
I believe the answer is:
at ease
'chilled-out demeanour' is the definition.
I can't judge whether this defines the answer.
'a kid with a' is the wordplay.
'a kid' becomes 'tease' (I've seen this before).
'with' means one lot of letters go next to another.
'tease' after 'a' is 'AT EASE'.
Can you help me to learn more?
(Other definitions for at ease that I've seen before include "unworried" , "Relax - that's an army order" , "Free from anxiety,in comfort" , "Free from discomfort - that's an order" , "resting" .)