When did the Battle of Sluys become a slaughter?

When does a battle with such unequal losses become a slaughter?

Sluys became a slaughter through encirclement, continued resistance, drowning, social barriers to surrender, and deliberate reprisals after capture.

The action became a slaughter, but the French continued fighting and had little practical route to surrender. Noble reluctance to yield to non-noble English companies further reduced the chance of quarter. Edward III's own letter described the French resistance as hard fighting, which cautions against treating the massacre as a collapse without combat. Captured commanders were executed in retaliation for earlier massacres and coastal raids, swimmers were attacked ashore, and fewer than one hundred French prisoners may have survived.