(1):

(v. i.) To deal unfairly; to practice secretly; to use bribery.

(2):

(v. i.) To meddle so as to alter, injure, or vitiate a thing.

(3):

(v. i.) To meddle; to be busy; to try little experiments; as, to tamper with a disease.

(4):

(n.) An instrument used in tamping; a tamping iron.

(5):

(n.) One who tamps; specifically, one who prepares for blasting, by filling the hole in which the charge is placed.