tamper1

[tam-per] /ˈtæm pər/
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.
Origin
1560-70; probably variant of temper (v.)
Related forms
tamperer, noun
untampered, adjective
Synonyms
1. interfere.
British Dictionary definitions for tamper with

tamper1

/ˈtæmpə/
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
Derived Forms
tamperer, noun
Word Origin
C16: alteration of temper (verb)

tamper2

/ˈtæmpə/
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
Word Origin and History for tamper with

tamper

v.

1560s, figurative use of tamper "to work in clay, etc., so as to mix it thoroughly," probably originally a variant of temper (v.), which is how it was initially spelled. Perhaps it is a dialectal workmen's pronunciation. Related: Tampered; tampering.

Idioms and Phrases with tamper with

tamper with

.
Interfere or meddle, especially in a harmful way. For example, If you tamper with that lock it's sure to break. [ c. 1600 ]
.
Engage in improper or secret dealings, as in He was accused of tampering with the jury. [ c. 1600 ]