Swear duck's missing from dish (5)
I believe the answer is:
curse
'swear' is the definition.
(I know that swear can be written as curse)
'duck's missing from dish' is the wordplay.
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'missing from' indicates named letters should be taken away.
'dish' becomes 'course'.
'course' with 'o' taken away is 'CURSE'.
(Other definitions for curse that I've seen before include "Malediction or expletive" , "Blaspheme; damn" , "Execrate" , "Swear - oath" , "Evil spell - oath" .)