Ragged dress covers old person sleeping rough (6)
I believe the answer is:
dosser
'person sleeping rough' is the definition.
'ragged dress covers old' is the wordplay.
'ragged' is an anagram indicator.
'covers' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'dress' with letters rearranged gives 'dsser'.
'dsser' going around 'o' is 'DOSSER'.
(Other definitions for dosser that I've seen before include "Hobo, tramp" , "Lazy person who does nothing" , "Idler, layabout" , "Vagrant who lives in cheap lodging house" , "In slang, an idle layabout" .)