Running into maltreated ragamuffin (14)
I believe the answer is:
tatterdemalion
'ragamuffin' is the definition.
(synonyms)
'running into maltreated' is the wordplay.
'running' indicates an anagram (the letters run around to different places).
'into'+'maltreated'='intomaltreated'
'intomaltreated' is an anagram of 'TATTERDEMALION'.
(Other definitions for tatterdemalion that I've seen before include "ragamuffin" , "Ragged fellow" .)