Abandoned decent leg manoeuvre (9)
I believe the answer is:
neglected
'abandoned' is the definition.
(thesaurus)
'decent leg manoeuvre' is the wordplay.
'manoeuvre' indicates an anagram.
'decent'+'leg'='decentleg'
'decentleg' anagrammed gives 'NEGLECTED'.
(Other definitions for neglected that I've seen before include "Disregarded or failed to do something" , "Not cared for" , "Treated carelessly" , "Ignored, left undone" , "Overlooked" .)