King, say, has month to hold on (7)
I believe the answer is:
monarch
'king say' is the definition.
(king is a kind of monarch)
'month to hold on' is the wordplay.
'month' becomes 'march' (March is an example**).
'to hold' is an insertion indicator.
'march' enclosing 'on' is 'MONARCH'.
'has' is the link.
(Other definitions for monarch that I've seen before include "one over realm?" , "Sovereign; butterfly" , "Stag in Landseer picture" , "Not a subject" , "Butterfly (emperor, say?)" .)