rebuke

Distinctions

tochachah (תוכחה)

Root י-כ-ח. Vilna Gaon: rebuke that comes from the mouth. Hashem's spoken warning of what will befall Yisrael if they abandon the Torah is called the Tochachah, and there are two (Vayikra 26:14-43, read before Shavuos; Devarim 28:15-68, read before Rosh Hashanah). Malbim sets out three differences, the who, the what, and the why: tochachah may pass even between equals; it is exclusively verbal, admonishing by logically proving that the other has done wrong; and it looks backward, castigating for past deeds (the Gaon also has this third point). Rabbi Shlomo Pappenheim: kin to nochach, opposite, since the rebuker stands against the rebuked in view and perhaps in place; and kin to hochachah, proof, and vikuach, debate. The most effective rebuke is not a direct confrontation but an "innocent" question that opens a debate, so the sinner sees the folly himself; fire-and-brimstone stirs a passing contrition, whereas tochachah proves the emptiness of sin and gives the mind grounds for a lasting acceptance to do good.

mussar (מוסר)

Root י-ס-ר. Vilna Gaon: rebuke that comes from the other limbs, not the mouth: a parent disciplining a child with a smack, Hashem teaching a man by afflicting him; hence the kinship with yissurin. Malbim: given by a person of authority to a subordinate; carried out by corporal punishment or by a tongue-lashing; and forward-looking, inculcating right behavior for the future. Pappenheim: kin to lehasir, to remove or separate, either because mussar removes the offender from the path of sin he was entrenched in, or because it marks the line between right and wrong; or else kin to assur, bound (the everyday "forbidden"), because the rebuker shows the other that he is bound to certain expectations. Rabbi Yaakov Tzvi Mecklenburg likewise: mussar is tying, since it gives a man the power to tie down his yetzer and hold his desires in check.

Rendering guidance

• The pair מוסר ותוכחת (as in Mishlei, e.g. 5:12): "discipline and reproof." Two words, and the order of the Hebrew.
• Tochachah standalone: "reproof" where the argument is the point, "rebuke" where the register is blunt. The two Torah passages keep their proper name, "the Tochachah."
• Mussar standalone in the sense of chastisement: "discipline," "chastisement," or "correction" (Malbim's future-facing sense); of Hashem's afflictions, "chastening." In the sense of the ethical discipline, "moral instruction," or the transliteration the project's ledger prescribes.
• Trap: "rebuke" absorbs both words, and "discipline" in English also names a field of study, which happens to match mussar's second sense but blurs the first. When a passage turns on the Gaon's mouth-versus-limbs line or Malbim's past-versus-future line, the English must show which word is which.
• Where a derashah draws on the kinship to yissurin (the Gaon), render yissurin "afflictions" or "sufferings" and keep mussar as "discipline," so the two stay visibly related.

Sources

Rabbi Reuven Chaim Klein, "Burke and Rebuke," What's in a Word?, Ohr Somayach, 24 Iyar 5777 (2017-05-20): raw text in sources/whats-in-a-word/raw/7260-burke-and-rebuke.md. Primary loci the article cites: Vayikra 19:17 (the mitzvah of rebuke); Vayikra 26:14-43 and Devarim 28:15-68 (the two Tochachos); the Vilna Gaon and Malbim on tochachah versus mussar; Rabbi Shlomo Pappenheim on nochach, hochachah, vikuach, lehasir, and assur. The Mishlei 5:12 pairing in the rendering guidance is supplied here as a worked example; the article does not cite it.