Slack water Meaning, Definition & Usage

  1. noun a stretch of water without current or movement
    slack.
    • suddenly they were in a slack and the water was motionless
  2. noun the occurrence of relatively still water at the turn of the (low) tide
    slack tide.

WordNet

Definitions
  1. the time when the tide runs slowly, or the water is at rest; or the interval between the flux and reflux of the tide.

Webster 1913