``Mucker'' is a word coined by the science fiction writer John Brunner in his great novel Stand on Zanzibar. The word derives from ``amok,'' which will require a bit of history. It is a Malay word, and a person who goes violently insane, rushing through the village and murderously attacking everyone in his path, is said to have ``run amok.'' In what was an egregiously idiotic statement, even for him, the eminent French critic Georges Bataille called running amok the purest manifestation of revolt, ``the movement by which man rises up against his own condition and the whole of creation.'' (Bataille never ran through the streets of Montparnasse madly slashing with a kris, so he either lacked the courage of his convicions or was a hypocrite with a small - a very small - modicum of brains.) The Malays, inevitably, were and are more sensible: they kill those who run amok.

A ``mucker,'' then, is someone who runs amok; the times havin' a-changed, now they use guns. As always, they are people driven to murderous madness by intolerable frustration, repression and conformity, whether in an isolated kampong or the Postal Service. So far muckers seem to have been mostly Americans, but just the other day the radio carried news of one in Germany.

It does Mr. Brunner's prescience great credit to have foreseen the need for this word, back in 1964; and it does the rest of us no credit at all, for letting such a word be needed.