Old English receleas "careless, thoughtless, heedless," earlier reccileas, from *rece, recce "care, heed," from reccan "to care" (see reck (v.)) + -less. The same affixed form is in German ruchlos, Dutch roekeloos "wicked." The root verb reck (Old English reccan) is passing into obscurity.
And in that very moment, away behind in some courtyard of the City, a cock crowed. Shrill and clear he crowed, recking nothing of wizardry or war, welcoming only the morning that in the sky far above the shadows of death was coming with the dawn. [Tolkien, "Return of the King"]