tamper

• (UK) IPA^(key): /ˈtæm.pə(ɹ)/

a railway ballast tamper

tamp +‎ -er

tamper (plural tampers)

1. A person or thing that tamps.
2. A tool used to tamp something down, such as tobacco in a pipe.
3. A railway vehicle used to tamp down ballast.
4. An envelope of neutron-reflecting material in a nuclear weapon, used to delay the expansion of the reacting material and thus produce a longer-lasting and more energetic explosion.

From Middle French temprer (“to temper, mix, meddle”). Doublet of temper.

tamper (third-person singular simple present tampers, present participle tampering, simple past and past participle tampered)

1. (intransitive) To alter by making unauthorized changes; to meddle.

   Synonym: tamper with

2. (in professional sports) To discuss future contracts against league rules with a player.

• empart, mat rep