Nedarim, Chapter 1, Mishnah 2. In the previous Mishnah we learned that the proper way to make a vow is to link it to a korban - to forbid something to oneself just as a korban is forbidden; and likewise one who wishes to forbid something with the language of cherem, or to accept nezirus upon himself. Our Mishnah teaches that a person need not use the original wording itself, but may instead use a substitute term (kinuy).
Examples of substitute terms:
"Konam", "Konach", "Konas" - one who tells his friend, at the time he makes his vow, that he does not want his friend to benefit from him, or that he does not want to benefit from his friend, and instead of the word korban he uses one of these expressions: "harei eilu kinuyin l'korban" - these are substitute terms for korban.
"Cherek", "Cherech", "Cheref" - one who wishes to forbid an object to himself as cherem, or to forbid his own objects to his friend as cherem, need not use specifically the word "cherem," but may say one of these substitute terms: "harei eilu kinuyin l'cherem" - these are substitute terms for cherem.
"Nazik", "Naziach", "Paziach" - one who vows nezirus need not say specifically "nazir": "harei eilu kinuyin l'nezirus" - these are substitute terms for nezirus.
"Shevusah", "Shekukah", "Mosa" - one who wishes to swear need not use the language of a shevuah, but may say one of these substitute terms, for example: "Imosa that I will not eat from this loaf" - he has made a "mosa," which functions as an oath, that he will not eat from the loaf: "harei eilu kinuyin l'shevuah" - these are substitute terms for an oath.
It is worth noting that "mosa" differs from "shevusah" and "shekukah," since it represents the Aramaic word "momasa," which in Aramaic means an oath.
The origin of these substitute terms - the dispute between Rabbi Yochanan and Reish Lakish:
Rabbi Yochanan: "the language of the nations" - these terms are drawn from the languages of other nations, who use them for vows, and we borrow these terms from them.
Reish Lakish: "a language that the Sages devised" - these are not the languages of the nations, but expressions that the Sages invented so that a person could make his vows using alternative formulations.
The reason the Sages instituted these substitute terms: if a person were to use the original wording, such as "korban," he might in the course of his words mention Hashem's Name - and especially with the word "korban," since "a korban to Hashem" is the language of the verse. And since we do not want a person to take Hashem's Name on his lips in vain, the Sages created other words for him to use.
In summary: in this Mishnah we learned the substitute terms with which a person may vow: "Konam, Konach, Konas" as substitutes for korban; "Cherek, Cherech, Cheref" as substitutes for cherem; "Nazik, Naziach, Paziach" as substitutes for nezirus; "Shevusah, Shekukah, Mosa" as substitutes for an oath. We examined the dispute between Rabbi Yochanan and Reish Lakish regarding the origin of these terms - the language of the nations or a language the Sages devised - and the reason for the enactment: preventing the mention of Hashem's Name at the time of the vow.