Gloomy corner church artist has come in to draw (10)
I believe the answer is:
sepulchral
'gloomy' is the definition.
(sepulchral means tomb-like)
'corner church artist has come in to draw' is the wordplay.
'corner' becomes 'SE' (south east corner of something).
'church' becomes 'ch' (common abbreviation).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'has come in to' indicates putting letters inside.
'draw' becomes 'pull' (pulling is a kind of drawing).
'ch'+'ra'='chra'
'chra' put within 'pull' is 'pulchral'.
'se'+'pulchral'='SEPULCHRAL'
(Other definitions for sepulchral that I've seen before include "from the grave" , "offering gloomy tones" .)