Teach artist to open some paint? (5)
I believe the answer is:
train
'teach' is the definition.
(training is a kind of teaching)
'artist to open some paint?' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'to open' indicates putting letters inside (some letters create an opening in a word).
'some paint?' becomes 'tin' (paint is often stored in a tin).
'ra' inserted into 'tin' is 'TRAIN'.
(Other definitions for train that I've seen before include "Locomotive plus carriages" , "Do exercises" , "Engine and carriages" , "Long back section of a gown that's drawn along the floor" , "held up in union action?" .)