slack water

slack water

n.

1. A period of cessation in the strong flow of a current of water, especially at high or low tide.

2. An area in a sea or river unaffected by currents; still water.

Thesaurus

Noun	1.	slack water - a stretch of water without current or movement; "suddenly they were in a slack and the water was motionless" slack stretch - a large and unbroken expanse or distance; "a stretch of highway"; "a stretch of clear water"
	2.	slack water - the occurrence of relatively still water at the turn of the (low) tide slack tide tide - the periodic rise and fall of the sea level under the gravitational pull of the moon