Lowry's first painting lacking substance? What about Turner? (5)
I believe the answer is:
lathe
'turner?' is the definition.
(a lathe is something which 'turns')
'lowry's first painting lacking substance? what about' is the wordplay.
'lowry's first' becomes 'l' (1st letter of 'lowry').
'painting' becomes 'art' (painting is an art).
'lacking substance?' means to remove the middle letters (remove the body or substance of the word).
'what' becomes 'eh' (sound used to ask 'what?' or 'pardon?').
'about' is a reversal indicator.
'art' with its centre taken out is 'at'.
'eh' in reverse letter order is 'he'.
'l'+'at'+'he'='LATHE'
(Other definitions for lathe that I've seen before include "piece of machinery" , "Machine for turning and shaping wood etc" , "Machine tool for shaping metal or wood" , "Rotating machine tool" , "This is turned out" .)