Satisfied after cure’s put paid to a nutcase (6)
I believe the answer is:
helmet
'nutcase' is the definition.
(both can mean a foolish person)
'satisfied after cure's put paid to a' is the wordplay.
'satisfied' becomes 'met' (as in 'met the conditions of his contract').
'after' is a charade indicator (letters next to each other).
'cure' becomes 'heal' (synonyms).
'put paid to' is a deletion indicator (to put pay to something is to stop it).
'heal' with 'a' taken out is 'hel'.
'met' put after 'hel' is 'HELMET'.
(Other definitions for helmet that I've seen before include "Hard hat" , "Safety hat" , "Police hat" , "Protective casing for the head" , "to provide capital protection" .)