1. Looseness; remissness; slowness; weakness.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• lackness,
• lockness,
• alackness,
• zlackness,
• xlackness,
• dlackness,
• elackness,
• wlackness,
• skackness,
• spackness,
• soackness,
• slacknesse,
• slakness,
• slacness,
• slacknes,
• snackness,
• slickness,
• sleckness,
• sleakness,
• saackless

• slicing,
• slacken,
• slickness,
• sleekness.

The adjective form of the word "slackness" is "slack".

The plural of the "slackness" can be the "slacknesses".

The singular of the "slackness" can be the "slackness".