Point that is most comprehensive (6)
I believe the answer is:
widest
'most comprehensive' is the definition.
('wide' can be similar in meaning to 'comprehensive')
'point that is' is the wordplay.
'point' becomes 'w' (W is an example).
'that is' becomes 'idest' ('id est' can be a synonym of 'that is').
'w'+'idest'='WIDEST'
(Other definitions for widest that I've seen before include "most spacious" , "Most broad" , "most off target" , "Broadest" , "most unplayable for batsman?" .)