Rare/archaic but attested use meaning ‘loosely, without tension’; important for completeness.
Translations
Keep the rope slack so the climber can adjust his harness.
Gardez la corde lâchement tendue afin que l’alpiniste puisse ajuster son harnais.
Definitions
Loosely; with reduced tension or tightness. Keep the rope slack so the climber can adjust his harness.