TAMPERING

To make unauthorized or improper alterations, sometimes causing deliberate damage; to meddle (with something).

Example: "The alarm had been tampered with and didn’t go off when it should have."

To try to influence someone, usually in an illegal or devious way; to try to deal (with someone).

Example: "Prosecutors argued that he would tamper with witnesses if bail was granted."

To meddle (with something) in order to corrupt or pervert it.

To involve oneself (in a plot, scheme, etc.).

To attempt to practise or administer something (especially medicine) without sufficient knowledge or qualifications.

(in professional sports) to discuss future contracts with a player, against league rules.