I start to support a married friend (5)
I believe the answer is:
amigo
'friend' is the definition.
('friend' in Spanish)
'i start to support a married' is the wordplay.
'start' becomes 'go' (synonyms).
'to support' means one lot of letters go next to another (in a down clue, some letters hold up others).
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'i'+'go'='igo'
'a'+'m'='am'
'igo' after 'am' is 'AMIGO'.
(Other definitions for amigo that I've seen before include "A Spanish pal" , "friend in Uruguay" , "Friend in Spanish-speaking areas" , "friend abroad" , "Friend in Spanish-speaking area" .)