What 3-letter word in English has an odd start, an even finish and an infinitely!

I do know this riddle!. The word is "vex"!. How do I know!? Because "v" is the Roman numeral for 5, which is odd!. "x" is the Roman 10, which is even!. "e" is the base of the natural logarithm!. It is an irrational number (i!.e!., e = 2!.718281828!.!.!.) whose mantissa (part to the left of the decimal point) is infinitely long!.
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following Skip Johnson (the previous answerer):
what about S E X
E and X is according to Skip Johnson
and S resembles 5!.!.!.!.!.!.!.!.!.:)Www@Enter-QA@Com

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catWww@Enter-QA@Com

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