Fool married - then sailed off (7)
I believe the answer is:
mislead
'fool' is the definition.
(I know that fool can be written as mislead)
'married then sailed off' is the wordplay.
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'then' is a charade indicator (letters next to each other).
'off' indicates an anagram.
'sailed' with letters rearranged gives 'islead'.
'm'+'islead'='MISLEAD'
(Other definitions for mislead that I've seen before include "Deceive" , "Fool" , "Cause someone to believe something is not true" , "Cause someone to have a false belief" , "Take someone in the wrong direction" .)