verb, modal particle · to call out to, greet, or say hello to

他热情地跟我打招呼。

verb · to notify, tell, or give a heads-up

去之前最好先打个招呼。

verb · to look after or take care of someone (e.g., guests)

我们要好好招呼客人。

verb · to take care or be careful that something negative does not happen

招呼别碰了头。