Extremes of man-eating shark? Correct! (4)
I believe the answer is:
mark
'correct' is the definition.
(thesaurus)
'extremes of man-eating shark?' is the wordplay.
'extremes of' says to hollow out the word (remove centre letters) (only the letters at the extremes of the word).
'man-eating shark?' becomes 'mackerel shark' (man-eating shark is a kind of mackerel shark).
'mackerelshark' with its centre taken out is 'MARK'.
(Other definitions for mark that I've seen before include "The second Gospel" , "Spot - old German coin - apostle" , "Scar; note" , "Indicate" , "What one might have paid old German" .)