use of it was forbidden among the soldiery by the army regulations of
those days; so in the Ordinances des Batailles in the ninth year of
Richard II, art. x.:

"Item, que nul soit si hardi de crier havoick sur peine d'avoir
la teste coupe."

This was properly a punishable offence in soldiers; havock being the cry
of mutual encouragement to general massacre, unlimited slaughter, that
no quarter should be given, &c. A tract on "The office of the constable
and Mareshall in the tyme of Warre," contained in the black book of the
Admiralty, has this passage:

"Also, that no man be so hardy to crye havock upon peyne that he
that is begynner shall be deede therefore: and the remanent that
doo the same, or follow, shall lose their horse and harneis ...
and his body in prison at the king's will."

And this appears to answer well to the original term, which is taken
from the ravages committed by a troop of wild beasts, wolves, lions,
&c., falling on a flock of sheep. But some think it was originally a
hunting term, importing the letting loose a pack of hounds. Shakspeare
combines both senses:

"Cry havock! and let slip the dogs of war."

In a copy of Johnson's _Dictionary_ before me, I find

"HAVOCK (haroc, Sax.), waste; wide and general devastation."
_Spenser_.