To put an end to; to do away with.
To block a process or function.
To annul by an authoritative act; to abolish by the authority of the maker or her or his successor; to repeal; — applied to the repeal of laws, decrees, ordinances, the abolition of customs, etc.
To reject something.
No.
Nothing; nix; often in the phrase "ixnay on ...", indicating something that must not be mentioned, often in Pig Latin