1
general::
Phrase(s): tamper with someone or something
to fiddle with someone or something; to meddle with someone or something. • I’ve got him believing just what I want him to believe. Don’t tamper with him. • Please don’t tamper with the thermostat.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
1. Interfere or meddle, especially in a harmful way. For example, If you tamper with that lock it's sure to break. [c. 1600] 2. Engage in improper or secret dealings, as in He was accused of tampering with the jury. [c. 1600]
American Heritage Idioms