Tidy in one attempt (4)
I believe the answer is:
neat
'tidy' is the definition.
(similar in meaning)
'in one attempt' is the wordplay.
'in' indicates the answer is hidden within the clue.
'NEAT' can be found hidden inside 'one attempt'.
(Other definitions for neat that I've seen before include "without ice?" , "well-kept" , "As whisky may be" , "Finished" , "Bovine animal" .)