Emily Dickinson Lexicon

SLACK, a. [Sax. slæc; Sw. slak; W. llac, yslac. See the Verb.]

1. Not tense; not hard drawn; not firmly extended; as, a slack rope; slack rigging.
2. Weak; remiss; not holding fast; as, a slack hand.
3. Remiss; backward; not using due diligence; not earnest or eager; as, slack in duty or service; slack in business.
4. Not violent; not rapid; slow; as, a slack pace. – Dryden. Slack in stays, in seamen's language, slow in going about; as a ship. – Mar. Dict. Slack water, in seamen's language, the time when the tide runs slowly, or the water is at rest; or the interval between the flux and reflux of the tide. Mar. Dict.