Tamper

verb (used without object)
1.
to meddle, especially for the purpose of altering, damaging, or misusing (usually followed by with):
Someone has been tampering with the lock.
2.
to make changes in something, especially in order to falsify (usually followed by with):
to tamper with official records.
3.
to engage secretly or improperly in something.
4.
to engage in underhand or corrupt dealings, especially in order to influence improperly (usually followed by with):
Any lawyer who tries to tamper with a jury should be disbarred.
noun
1.
a person or thing that tamps.
verb (intransitive)
1.
(usually foll by with) to interfere or meddle
2.
to use corrupt practices such as bribery or blackmail
3.
(usually foll by with) to attempt to influence or corrupt, esp by bribery: to tamper with the jury
noun
1.
a person or thing that tamps, esp an instrument for packing down tobacco in a pipe
2.
a casing around the core of a nuclear weapon to increase its efficiency by reflecting neutrons and delaying the expansion