Moan about district's first vagrant (5)
I believe the answer is:
nomad
'vagrant' is the definition.
(thesaurus)
'moan about district's first' is the wordplay.
'about' indicates an anagram.
'district's first' becomes 'd' (1st letter of 'district').
'moan' anagrammed gives 'noma'.
'noma'+'d'='NOMAD'
(Other definitions for nomad that I've seen before include "Person wandering" , "Roving person" , "wandering type" , "being domestically unstable" , "Member of a wandering pastoral community" .)