bedimos

How did the word בְּדִימוֹס bedimos (sometimes pronounced bedimus) come to mean "retired, emeritus "?

In Talmudic literature, we find the word dimos דִימוֹס meaning "pardoned, acquitted." For example:

 אמר לו הואיל והאמנתי עליך דימוס פטור אתה

"The officer said to him: Since you put your trust in me, you are acquitted [dimos]; you are exempt." (Bavli Avoda Zara 16b)

 בְּנוֹהַג שֶׁבְּעוֹלָם מֶלֶךְ בָּשָׂר וָדָם יוֹשֵׁב וְדָן כְּשֶׁהוּא נוֹתֵן דִּימוּס הַכֹּל מְקַלְּסִין אוֹתוֹ

"Usually in the world, if a king of flesh and blood sits in judgment, if he dismisses [dimus] (=throws out the indictment), everybody acclaims him." (Yerushalmi Berachot 9:5)

Klein provides the following etymology:

דִּימוֹס m.n.  PBH  1 he was freed, was acquitted.   NH  2 he resigned (from office).  [Probably from Latin dīmissus, p. part. of dīmittere (= to send away, dismiss, release), from dī– (= apart, asunder), and mittere (= to send). .] 

This makes dimos cognate with the English "dismiss":

early 15c., dismissen, "release from court restraint or legal charges;" late 15c., "remove from office, service, or employment," apparently from Latin dimissus, past participle of dimittere "send away, send different ways; break up, discharge; renounce, abandon," 

But I asked about the form bedimos. Where does it come from?

We also find it in Rabbinic Hebrew. For example here:

בִּשְׁתֵּים עֶשְׂרֵה יָצָא בְּדִימוּס. אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא לְאָדָם, זֶה סִימָן לְבָנֶיךָ כְּשֵׁם שֶׁעָמַדְתָּ לְפָנַי בַּדִּין הַיּוֹם הַזֶּה וְיָצָאתָ בְּדִימוּס, כָּךְ עֲתִידִין בָּנֶיךָ לַעֲמֹד לְפָנַי בַּדִּין בְּיוֹם זֶה וְיוֹצְאִין לְפָנַי בְּדִימוּס, אֵימָתַי בַּחֹדֶשׁ הַשְּׁבִיעִי בְּאֶחָד לַחֹדֶשׁ.

"In the twelfth [month], [Adam] was pardoned [yatza bedimus]. The Holy One, blessed be He, said to Adam, 'This is a sign for your children: In the same way that you stood in front of Me in judgement on this day and were pardoned, so too in the future will your children stand in front of Me in judgement on this day and be pardoned in front of Me.'" (Vayikra Rabbah 29:1)

This is the meaning until modern times. Why then, did it change from "pardoned" to "retired"?

The linguist Elon Gilad answers the question in this article. He notes that the first time we find the modern sense of the word is in 1890, when Nahum Sokolow wrote in his newspaper that "before Bismarck retired [yatza bedimos]..." After writing that phrase, "יצא ביסמארק בדימוּס", he adds the following word in parentheses: דימיסיאן. Sokolow does not note what language this foreign word is being transliterated from. 

Gilad proposes it's a Yiddish word, coming from the Polish dymisja, meaning "resignation" or "dismissal" from a position. His theory is that this Yiddish meaning is what influenced the change in meaning in Modern Hebrew. Zuckermann here concurs, noting other European languages with cognate words with similar meanings, including Russian demissiya, French demission, and Italian dimissioni. All of these words derive from the Latin dimissio and dimittere (to send away, dismiss) - just as the Hebrew dimos does. The only difference is that dimos took on the sense of "freed from judgement," while the European words also included "freed from a position," i.e., "resigned."

In Gilad's article, he continues by writing that the phrase yatza bedimos spread widely in the early 20th century, and by the 1930s, retired officers were already being referred to simply with the phrase bedimos (without the verb yatza). By the middle of the century, bedimos had generally replaced yatza bedimos. It is typically used to refer to people who retired from high-level positions, like judges or military officers. The word dimos, without the preposition be, is rarely, if ever, found in Hebrew today.