Sneaky sort losing wide artistic support (5)
I believe the answer is:
easel
'artistic support' is the definition.
(I've seen this before)
'sneaky sort losing wide' is the wordplay.
'sneaky sort' becomes 'weasel' (I've seen this in another clue).
'losing' suggests deleting specific letters.
'wide' becomes 'w' (abbreviation e.g. in cricket).
'weasel' with 'w' taken away is 'EASEL'.
(Other definitions for easel that I've seen before include "Painter's support" , "dead-headed plant" , "supporter of the arts" , "Artist's prop" , "Framework to hold a canvas" .)