Royal family's supported by government (4)
I believe the answer is:
king
'royal' is the definition.
(a king is royal)
'family's supported by government' is the wordplay.
'family' becomes 'kin' (synonyms).
'supported by' is a charade indicator (letters next to each other) (in a down clue, some letters hold up others).
'government' becomes 'g' (abbreviation for government).
'kin'+'g'='KING'
(Other definitions for king that I've seen before include "See 22" , "Male on the throne" , "Male monarch" , "Playing card" , "Eponymous giant ape in movie" .)