Man came down with old wife (6)
I believe the answer is:
fellow
'man' is the definition.
(fellow is a kind of man)
'came down with old wife' is the wordplay.
'came down' becomes 'fell' (I've seen this in other clues).
'with' means one lot of letters go next to another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'wife' becomes 'w'.
'fell'+'o'+'w'='FELLOW'
(Other definitions for fellow that I've seen before include "Academic chap?" , "Kind of associate, may be a traveller with communism" , "The other of a pair - just a chap" , "Senior member of a college or university" , "Informally, a man, or the other of a pair" .)