Girl left atmosphere (5)
I believe the answer is:
laura
'girl' is the definition.
(girl's name)
'left atmosphere' is the wordplay.
'left' becomes 'l' (common abbreviation).
'atmosphere' becomes 'aura' (synonyms).
'l'+'aura'='LAURA'
(Other definitions for laura that I've seen before include "Cells of a group of recluses" , "US First Lady" , "- Ashley, Welsh clothes, furnishings designer" , "- Ashley, Welsh clothing and furniture designer" , "Girl's name" .)