Poor family dumped in street (5)
I believe the answer is:
skint
'poor' is the definition.
('skint' can be similar in meaning to 'poor')
'family dumped in street' is the wordplay.
'family' becomes 'kin' ('kin' can be a synonym of 'family').
'dumped in' indicates putting letters inside.
'street' becomes 'st'.
'kin' placed into 'st' is 'SKINT'.
(Other definitions for skint that I've seen before include "Having little money" , "Hard up (slang)" , "Stony broke" , "On one's uppers" , "Impecunious" .)