Smack1  —n. 1 sharp slap or blow. 2 hard hit at cricket etc. 3 loud kiss. 4 loud sharp sound. —v. 1 slap. 2 part (one's lips) noisily in anticipation of food. 3 move, hit, etc., with a smack. —adv. Colloq. 1 with a smack. 2 suddenly; directly; violently. 3 exactly (smack in the centre).  a smack in the eye (or face) colloq. Rebuff; setback. [imitative]