Swear nothing is taken from path (5)
I believe the answer is:
curse
'swear' is the definition.
(I know that swear can be written as curse)
'nothing is taken from path' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'is taken from' is a deletion indicator.
'path' becomes 'course' (synonyms).
'course' with 'o' removed is 'CURSE'.
(Other definitions for curse that I've seen before include "Blaspheme; damn" , "Invoke evil upon" , "Execration" , "Excommunication" , "Profanity" .)