havoc

Concise Oxford English Dictionary © 2008 Oxford University Press:
havoc/ˈhavək/

▶noun

• 1 widespread destruction.

• 2 great confusion or disorder.

▶verb (havocs, havocking, havocked) archaic lay waste to.

– phrases
play havoc with completely disrupt.

– origin ME: from Anglo-Norman Fr. havok, alt. of OFr. havot, of unknown origin; the word was orig. used in the phr. cry havoc ‘give an army the order havoc’, which was the signal for plundering.