Getting in on the action with my reproduction of a 1738 Haggadah from Altona, Germany.
I used it this year and discovered some errors in it. A rather conspicuous one occurred as it was my turn to read "דָבָר אַחֵר: בְּיָד חֲזָקָה שְׁתַּיִם, וּבִזְרֹעַ נְטוּיָה שְׁתַּיִם, וּבְמֹרָא גָּדֹל - שְׁתַּיִם, וּבְאֹתוֹת - שְׁתַּיִם, וּבְמֹפְתִים - שְׁתַּיִם." It was missing one of the list items, which i didn't notice until everyone corrected me.
What are slang terms that people on Mi Yodeya use in comments or chat that are unique to this community?
Please post one term with definition, etymology, earliest known usage, etc., per answer.
Please only include terms that can reasonably be considered to genuinely be part of the communal ling...