Longman Dictionary of Contemporary English - smack

~1 v 1 to hit a child with your hand in order to punish them  (To bed now, or I'll smack your bottom!) 2 to hit something against something else so that it makes a short loud noise  (smack sth against/into etc)  (He smacked his fist against his palm.) 3 smack your lips to make a short loud noise with your lips because you are hungry 4 BrE informal to hit someone hard with your closed hand; punch1 (1)  (Say that again and I'll smack you!) smack of sth phr v if something smacks of dishonesty, desperation etc it seems to contain some of that quality  (I don't want to say anything that smacks of disloyalty.) ~2 n 1 a) a hit made with your hand held flat, especially to punish a child  (Quiet, or I'll give you a smack!) b) BrE informal a hard hit with your closed hand; punch2 (1) 2 a short loud noise caused especially when something hits something else 3 give sb a smack on the lips/cheek informal to kiss someone 4 have a smack at BrE informal to try to do something 5 slang heroin (=a dangerous illegal drug) 6 a small fishing boat ~3 adv informal 1 exactly or directly in the middle or in front of something  (smack in the middle/in front of etc)  (There was a hole smack in the middle of the floor. | smack-bang BrE /smack-dab AmE)  (The plane was stuck there, smack-dab in the middle of the lake!) 2 if something moves smack into or against something, it hits it with a lot of force, making a loud noise  (The car ran smack into the side of the bus.)