verb.to interfere so as to weaken or change for the worse —used with with

• was charged with tampering with consumer products

verb.to try foolish or dangerous experiments —used with with

verb.to render something harmful or dangerous by altering its structure or composition

noun.a tool for tamping: tamp

• Using a tamper, tamp the coffee down into the filter …
• After each truckload of earth fell onto the cobblestones of the Piazza's perimeter, a steamroller flattened it, and five relaxed-looking workmen … patted it smooth with shovels and wooden tampers, and hosed it down.