Another peeve of mine: "categorically" as in "It is categorically untrue that Abraham Lincoln freed the slaves in 1832."

Apparently the word is substituted for "absolutely" or "completely", but every time I hear it, I wonder what unstated category the speaker has in mind. It doesn't help that those who use it often sound like they are trying to put over a snowjob.
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Re: the mail. In the U.S. we call them letter carriers.