WordWeb Online

1. A person who shirks his work or duty (especially one who tries to evade military service in wartime)
   - shirker

1. Not tense or taut
   "slack and wrinkled skin"; "slack sails"; "a slack rope"
   - loose
    
2. Flowing with little speed as e.g. at the turning of the tide
   "slack water"
    
3. Lacking in rigour or strictness
   "slack in maintaining discipline"
   - lax

Derived forms: slackers

See also: lax, negligent, slack, slackly, slackness, standing

Type of: bum [N. Amer], do-nothing, idler, layabout, loafer

Encyclopedia: Slack