Run Rampant Meaning
(idiomatic) To go unchecked or without control; to be wild or excessive.
Example: The weeds had long run rampant in the garden and it would be difficult to regain control.
2012 March 1, William E. Carter, Merri Sue Carter, â€œThe British Longitude Act Reconsideredâ€, American Scientist, volume 100, number 2, page 87:
Conditions were horrendous aboard most British naval vessels at the time. Scurvy and other diseases ran rampant, killing more seamen each year than all other causes combined, including combat.