Still clutching front of Sunday supplement (6)
But I've got no explanation for this one! Could you help me understand?
(Other definitions for insure that I've seen before include "Protect value through contract" , "Take out cover" , "Protect (something) against loss" , "Provide protection against risk or damage" , "do business at Lloyds?" .)
'supplement' is the definition.
(insert is a kind of supplement)
'still clutching front of sunday' is the wordplay.
'still' becomes 'inert' (I've seen this before).
'clutching' is an insertion indicator.
'front of sunday' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inert' going around 's' is 'INSERT'.
Can you help me to learn more?
(Other definitions for insert that I've seen before include "Put thing in between others" , "Place in between other things" , "Place within, pages of a publication say" , "Put between or within other things" , "supplement" .)