"But Mike would also have agreed," Mahmoud went on, "if I had named a hundred other English words, words which represent what we think of as different concepts, even pairs of antithetical concepts.  And 'grok' means all of these, depending on how you use it.  It means 'fear,' it means 'love,' it means 'hate' - proper hate, for by the Martian 'map' you cannot possibly hate anything unless you grok it completely, understand it so thoroughly that you merge with it and it merges with you - then and only then can you hate it.  By hating yourself. But this also implies, by necessity, that you love it, too, and cherish it and would not have it otherwise.  Then you can hate - and (I think) that Martian hate is an emotion so black that the nearest human equivalent could only be called a mild distaste."