A guy, free from anxiety (2,4)
I believe the answer is:
at ease
'free from anxiety' is the definition.
(I've seen this before)
'a guy' is the wordplay.
'guy' becomes 'tease' (I've seen this before).
'a'+'tease'='AT EASE'
(Other definitions for at ease that I've seen before include "Relax - that's an army order" , "Free from discomfort - that's an order" , "Army command to relax, stand with feet apart" , "Free from anxiety,in comfort" , "Relaxed, not tense - that's an order" .)