run rampant

phrase

: to be very common or to spread very quickly and in a way that is difficult to control

Rumors of her engagement ran rampant.

Examples of run rampant in a Sentence

Recent Examples on the Web

Speculation has run rampant, entirely unconfirmed to date, that Swift might be targeting this fall to release a deluxe edition of her 2006 debut album. — Chris Willman, Variety, 21 Sep. 2026

And because measles is so infectious, even a small slip in vaccine coverage can allow the virus to run rampant. — Lauren J. Young, Scientific American, 18 Sep. 2026

Over in Marvel’s territory, the X-Men had their whole chronology readjusted when a time-traveling mutant killed off Professor Charles Xavier, allowing Apocalypse to run rampant. — Daniel Dockery, Vulture, 24 Aug. 2026

Cucumbers turn bitter, tomato flowers shrivel, leaves wilt, and pests such as whiteflies and spider mites run rampant across the fields. — Taylor Luck, Christian Science Monitor, 17 Aug. 2026