Artist withdrawn after snorting line recklessly (6)
I believe the answer is:
rashly
'recklessly' is the definition.
(synonyms)
'artist withdrawn after snorting line' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'withdrawn' becomes 'shy' (both can mean reserved or timid).
'after' says to put letters next to each other.
'snorting' means one lot of letters goes inside another (snort can mean to ingest through the nose).
'line' becomes 'l' (used when specifying particular lines from a poem).
'ra'+'shy'='rashy'
'rashy' placed around 'l' is 'RASHLY'.
(Other definitions for rashly that I've seen before include "in reckless fashion" , "Recklessly" , "In a hasty and foolhardy manner" , "Without forethought" , "Without caution" .)