step on

(transitive) To oppress or mistreat (a person).

(recreational drugs, transitive) To adulterate (a drug) for the purpose of increasing its bulk, and therefore the profit when sold; to dilute, cut.

(radio communications, transitive) To interrupt, overpower, or override (another transmission on the same frequency) with one's own transmission.

(transitive, slang) To intrude on someone else's turf or portfolio.

(intransitive, dated) To approach as to confront or fight.

Used other than figuratively or idiomatically: see step, on.