Having become cooler, going out, clad myself in (6)
I believe the answer is:
calmed
'having become cooler going' is the definition.
I can't judge whether this definition defines the answer.
'out clad myself in' is the wordplay.
'out' indicates an anagram.
'myself' becomes 'me'.
'in' indicates putting letters inside.
'clad' with letters rearranged gives 'cald'.
'cald' going around 'me' is 'CALMED'.
Can you help me to learn more?
(Other definitions for calmed that I've seen before include "Pacified, dispelled anger" , "Made peaceful, pacified" , "relaxed" , "Soothed" , "Placated, made peaceful" .)