I still think it is much too verbose for something as straightforward as calling a function. In addition, if you type "(keyw[TAB]" in a smart REPL you'll get a choice of keyword-call or keyword-lambda.
I admit that ":", my original suggestion, is probably *too* short and should be left to the user. But I really really want something with ~ 3 letters. Let's try to find one. My best shot right now is "kwc".