Webster's Revised Unabridged Dictionary · 1913

Onslaught

Onslaught , noun

[Old English on on + slaught, slaht, slaughter. See Slaughter.]

1.
An attack; an onset; esp., a furious or murderous attack or assault.
By storm and onslaught to proceed. — Hudibras
2.
A bloody fray or battle. [Scottish] — Jamieson