smack that 點解

smack = 揼扁

唔知你從那裏看到
如果只是這兩個字smack that無其他句的話
是一句俚語
意思是
癈的
或
不用理會
或
去死吧
咁上下意思
要看之前講的是甚麼
就是對那東西/事情採取攻擊或否定的態度

你一定是查過字典，但將解釋放回原文仍然解不通才會發問。所以你不將原文寫出來，我們可能很難幫你。

smack 一般解拍。像 smack that fly 拍烏蠅。



2012-02-25 14:47:51 補充：
If it is from a rapper song title, it probably means 不用理會 , 睬佢都傻。

smack(verb) is to hit somebody with your open hand,especially as a punishment:-eg.I think it's wrong to smack children (=spank,slap,pat,)eg:-to smack someone on the wrist." Smack that "has a meaning of smack something;eg. to put something somewhere with a lot of force so that it makes a loud noise. eg.He smacked a fist into the broken chair. Smack somebody up has a meaning of to hit somebody hard with your hand,many times. "that" means a pronoun used for referring to a person or thing that is not near the speaker.Hence "that" may use for referring to a thing.