(United States) behavior noun. 1. manner of conducting oneself, kelakuan, tingkah laku; (towards someone) kelakuan: his behaviour at the party was disgraceful, kelakuannya di majlis itu memalukan; good behaviour, kelakuan baik; be on one’s best behaviour, berkelakuan baik; 2. (psychology) tingkah laku; 3. action, reaction of something under given circumstances, a. (of chemical substance, metal, etc) tindakan; b. (of machine etc) perjalanan.