slack up slack-twisted • slack water · · · Info · Definitions · Synonyms · Characters · · slack up · · Text Common · · Latin · · Scripts 8 · · Length 2 · · Syllables Definitions · · · (verb) make less active or fast. Synonyms: slack, slacken, slack up, relax. Examples: "He slackened his pace as he got tired." "Don't relax your efforts now." · · Verb Definition 1 Synonyms · · · slack · · Synonym 1 slacken · · Synonym 2 relax · · Synonym 3 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 k latin small letter k U+006B l latin small letter l U+006C p latin small letter p U+0070 s latin small letter s U+0073 u latin small letter u U+0075