The first DIY turned out smart (4)
I believe the answer is:
tidy
'smart' is the definition.
(similar in meaning)
'the first diy turned out' is the wordplay.
'the first' becomes 't' (1st letter of 'the').
'turned out' is an anagram indicator (turn out can mean to organise).
'diy' with letters rearranged gives 'idy'.
't'+'idy'='TIDY'
(Other definitions for tidy that I've seen before include "Considerable (sum); neat" , "Substantial - orderly" , "generous" , "Shipshape" , "Neat - container for odds and ends" .)