… poor family to be thrown into street (5)
I believe the answer is:
skint
'poor' is the definition.
(similar in meaning)
'family to be thrown into street' is the wordplay.
'family' becomes 'kin' (synonyms).
'to be thrown into' indicates putting letters inside.
'street' becomes 'st' (abbreviation).
'kin' inserted inside 'st' is 'SKINT'.
(Other definitions for skint that I've seen before include "Having little money" , "Hard-up" , "Without money (slang)" , "Informally, having no money left" , "On one's uppers" .)