Craftsman's mother and child (5)
I believe the answer is:
mason
'craftsman's' is the definition.
(I know this)
'mother and child' is the wordplay.
'mother' becomes 'ma' (Ma is another word for mother or mum).
'and' is a charade indicator (letters next to each other).
'child' becomes 'son' (son is a kind of child).
'ma'+'son'='MASON'
(Other definitions for mason that I've seen before include "One works with stone or brick" , "Secret society member" , "One is skilful with stone" , "figure in lodge" , "Craftsman working in stone" .)