Achievement staying in safe atmosphere! (4)
I believe the answer is:
feat
'achievement' is the definition.
(feat is a kind of achievement)
'in safe atmosphere' is the wordplay.
'in' says the answer is hidden in the clue.
'FEAT' is hidden within 'safe atmosphere'.
'staying' acts as a link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for feat that I've seen before include "Courageous act" , "Achievement needing skill, strength, etc." , "Significant achievement" , "An accomplishment of fate" , "Notable achievement" .)