A person or thing that tamps.

A tool used to tamp something down, such as tobacco in a pipe.

(rail transport) A railway vehicle used to tamp down ballast.

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.

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

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

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

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

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

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