WordWeb Online

1. Characteristic of or befitting a slut or slattern; used especially of women
   "While Scouse was at the bar, the sluttish blonde looked at us";
   - blowsy [informal], blowzy [informal], slatternly [archaic], tarty [informal], slutty [informal]
    
2. Casual and unrestrained in sexual behaviour
   "her sluttish virtue";
   - easy, loose, promiscuous, wanton, tarty [informal], slutty [informal]

See also: unchaste, untidy

Encyclopedia: Sluttish