Artist brought up one boy (4)
I believe the answer is:
dali
'artist' is the definition.
(I've seen this before)
'brought up one boy' is the wordplay.
'brought up' shows that the letters should be reversed in order (down clues only).
'one' becomes 'i' (Roman numeral).
'boy' becomes 'lad' (lad is a kind of boy**).
'i'+'lad'='ilad'
'ilad' backwards is 'DALI'.
(Other definitions for dali that I've seen before include "Salvador --, twentieth century Spanish surrealist painter" , "Controversial painter" , "Tree" , "Salvador -, twentieth century artist" , "Surrealist Spanish painter, d. 1989" .)