Mark married in unconscious state (5)
I believe the answer is:
comma
'mark' is the definition.
(punctuation mark)
'married in unconscious state' is the wordplay.
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'in' is an insertion indicator.
'unconscious state' becomes 'coma' (I've seen this before).
'm' inserted inside 'coma' is 'COMMA'.
(Other definitions for comma that I've seen before include "repeatedly found in lists" , ", which gives us pause" , "Short break" , "Butterfly with orange and brown wings" , "List-item separator" .)