9780899067124 - Schottenstein Bavli Niddah volume one, published by Mesorah

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13b, note 5:

Chasam Sofer speculates that perhaps the printers erred, and R' Ami actually stated: One who arouses himself is called a מוּמָר...The above is, in fact, Rosh's version of the text.

The word מומר was invented by censors who disliked the word משומד, so it does not in fact appear in the uncensored edition of Rosh which reads משומד. This is also the reading of the earliest editions of the Talmud and of every extant Talmudic manuscript so without a doubt the correct reading is משומד and not מומר or עבריין. It is unfortunate Schottenstein did not have the courage to restore the correct text.