Relatives are in the street and really poor (5)
I believe the answer is:
skint
'really poor' is the definition.
'skint' can be an answer for 'poor' (similar in meaning). I am not certain of the 'really' bit.
'relatives are in the street' is the wordplay.
'relatives' becomes 'kin' (I've seen this before).
'are in the' is an insertion indicator.
'street' becomes 'st'.
'kin' going inside 'st' is 'SKINT'.
'and' is the link.
Can you help me to learn more?
(Other definitions for skint that I've seen before include "Strapped for cash" , "Impecunious" , "bust" , "Broke (sl.)" , "Having little money" .)