(Wibbles and Frubbles piss me off too.)
I actually love 'grok', and while it's pretty necessary to read Stranger in a Strange Land to get its full flavor, I can do a fast synopsis for those who can't/won't read it.
HEINLEIN SPOILER ALERT:
grok: Martian verb, literally 'to drink'. Abstract translations include (but are not limited to): 'to have sex with', 'to understand fully', 'to know and cherish the whole of', 'to accept'.
There's an idea in Stranger... that grokking someone, 'knowing them in fullness', is partially achieved through sex. A traditional phrase upon grokking someone through a meaningful sexual encounter is 'Thou art god'. I find that beautiful, and truthful, in that I see a side of each love in my constellation through sexual intimacy that I would not see otherwise.
If you can't stand Heinlein, I don't mind. He's dogmatic and idealistic to the point of naivete, but I still cry every time I read the last few chapters.
"I was thorough when I looked for you, and I feel justified lying in your arms." - Chasing Amy