Copyright 1997 Times Mirror Company Los Angeles Times December 14, 1997, Sunday, Home Edition Calendar; Page 95; Calendar Desk GRECIAN FORMULA Interesting couple of letters about Xena, the Warrior Princess (Dec. 7). Jack Grimshaw should be advised that H.L. Mencken said that "no one ever went broke underestimating the taste of the American people," not "intelligence." Robert L. Brown seems to have missed the whole point. Xena's portrayal is not of an "empty-headed, ambiguously sexed Amazon." Au contraire. Ms. Princess always thinks clearly and battles on the side of truth, justice and, uh, the Grecian way. Brown's objection to Xena's ability to use weapons sounds threatened and strangely quaint in this era when more women than ever are learning such skills as they vow to not be victims. As to Brown's objection to Xena's beating up men, well, they are the vicious, murdering bad guys in the stories, after all. (And she has also thrashed evil women, so fair's fair.) Exactly what would Brown have a rescuer, real or fictional, do in such circumstances? As to Xena's being "ambiguously sexed," perhaps Brown needs to get his television fixed. TOM BURNS Mesa, Ariz. * Bartlett's Quotations gives both "taste" and "intelligence" as acceptable versions of a quip that can only be "attributed" to Mencken. May Xena shield us from confusion over word origins. Anne Beatts started it by saying Xena buckles a fine swash ("Princess of the Xeitgeist," Nov. 30). Alfonzo Smith confounds it by writing, "one does not buckle a swash. One swashes one's buckle." In fact, if one is so inclined, one swashes a buckler, a small shield with a metal boss or knob. CHRIS VOGLER Venice