Poor family is in the way (5)
I believe the answer is:
skint
'poor' is the definition.
(similar in meaning)
'family is in the way' is the wordplay.
'family' becomes 'kin' (synonyms).
'is in the' indicates putting letters inside.
'way' becomes 'st' (abbreviation for street).
'kin' going into 'st' is 'SKINT'.
(Other definitions for skint that I've seen before include "Broke (sl.)" , "Hard up (sl.)" , "Without money (slang)" , "Penniless (slang)" , "Extremely poor" .)