- Present participle of havoc.
1922, Carpenter, volume 42, United Brotherhood of Carpenters and Joiners of America, page 19:
- […] [A]n unrelenting U-Boat warfarewas havocing the coasts, the hope and prayer of a stricket world was America, the Yankees.
1991, Justin Wintle, chapter 1989, Romancing Vietnam: Inside the Boat Country, edition Second edition, Signal Books, ISBN 9781904955153, published 2006, Thursday 9th November: Vinh-Dong Ha (Quang Tri Province), page 203:
- If I don’t sleep well again it’s not only because there are more drunken can bo' at one or two in the morning, havocing a fair disturbance outside my room. It’s because my head’s too full.
- The spelling havocking is more common.