The Lord is not slack concerning his promise, as some men count slackness. 2 Pet. iii. 9.

C(?)sar . . . about sunset, hoisting sail with a slack southwest, at midnight was becalmed. Milton.

Slack in stays (Naut.), slow in going about, as a ship. -- Slack water, the time when the tide runs slowly, or the water is at rest; or the interval between the flux and reflux of the tide. -- Slack-water navigation, navigation in a stream the depth of which has been increased, and the current diminished, by a dam or dams.

Syn. -- Loose; relaxed; weak; remiss; backward; abated; diminished; inactive; slow; tardy; dull.

Whence these raging fires
Will slacken, if his breath stir not their flames. Milton.

That through your death your lineage should slack. Chaucer.

They will not of that firste purpose slack. Chaucer.

Slack not the pressage. Dryden.

I should be grieved, young prince, to think my presence
Unbent your thoughts, and slackened 'em to arms. Addison.

In this business of growing rich, poor men should slack their pace. South.

With such delay
Well plased, they slack their course. Milton.

To respite, or deceive, or slack thy pain
Of this ill mansion. Milton.

Air-slacked lime, lime slacked by exposure to the air, in consequence of the absorption of carton dioxide and water, by which it is converted into carbonate of lime and hydrate of lime.