Shabbos, Chapter Ten, Mishnah 6. This mishnah deals with a series of actions in which the Tanna'im disagree as to whether they involve a Torah prohibition of melachah or only a rabbinic prohibition.
The text of the mishnah:
"HaNotel tzipornav zu bazu o b'shinav, v'chen se'aro, v'chen sefamo, v'chen zekano, v'chen hagodeles, v'chen hakocheles, v'chen hapokeses - Rabbi Eliezer mechayev, vachachamim osrim mishum shevus" - One who removes his nails with one another or with his teeth, and likewise his hair, and likewise his mustache, and likewise his beard, and likewise the woman who braids, and likewise the one who applies eye paint, and likewise the one who sets her hair - Rabbi Eliezer holds him liable, and the Sages forbid it as a shevus.
The cases in detail:
"HaNotel tzipornav zu bazu o b'shinav" - a person who cuts his nails without using a utensil, but rather peels them off with the nails of his other hand or removes them with his teeth. There is a possible liability here on account of shearing on Shabbos.
"V'chen se'aro, v'chen sefamo, v'chen zekano" - and the same law applies to one who removes the hair of his head, his mustache or his beard with his hands, not in the usual manner.
"V'chen hagodeles" - a woman who braids her hair on Shabbos in an intricate braid, and there is a possibility that this involves building.
"V'chen hakocheles" - a woman who uses makeup that colors the face, and there is a possibility that this involves dyeing on Shabbos.
"V'chen hapokeses" - the commentators disagree about the definition of this act: some say it is arranging the hair in a way that creates a part in the hair, and some say it is a particular type of coloring makeup. According to the first explanation it would involve building, and according to the second explanation, dyeing.
The dispute between Rabbi Eliezer and the Sages:
Rabbi Eliezer holds him liable: even though the removal of the nails or hair is done in a manner that is not the most efficient, it is still considered a Torah violation. The same law applies to the other acts of grooming and beautifying listed in the mishnah.
And the Sages forbid it as a shevus: all of these are forbidden by rabbinic law only. Removing hair or nails in this awkward manner is not a Torah violation, because it was done in a deviation from the usual manner. So too, a woman's arranging of her hair and applying makeup - these involve no Torah prohibition.
One who detaches from a perforated flowerpot:
One who detaches a plant from a perforated flowerpot is liable. Even though the plant grows in a pot and not in the ground, the hole in the pot creates a connection between the soil inside it and the soil of the ground, and therefore the pot is considered attached to the ground. But with a pot that is not perforated he is exempt, since the plant is not considered as growing from the ground, and uprooting it does not constitute detaching.
Rabbi Shimon disagrees and says that even in a perforated pot the plant is not considered as growing from the ground, and detaching it involves no Torah prohibition on Shabbos.
In summary: in this mishnah we learned a series of actions done in an unusual manner, or that have an aspect of shearing, building and dyeing - removing nails and hair without a utensil, braiding, applying eye paint and setting the hair. Rabbi Eliezer holds one liable for them by Torah law, and the Sages forbid them as a shevus only. We also examined the law of one who detaches from a perforated flowerpot, who is liable because the hole connects it to the ground, and the view of Rabbi Shimon, who exempts even with a perforated pot.