Kludge
Etymology
Popularized in a tongue-in-cheek 1962 article by Jackson Granholm in the computing magazine Datamation, defining it as an ill-assorted collection of parts making a barely working whole. Its deeper origin is uncertain; one guess links it to German "klug" ("clever"), which would make the name self-mockingly ironic. Even its spelling and pronunciation are disputed, with "kludge" and "kluge" both in use.
noun · /KLOOJ/
A clumsy, inelegant solution that nonetheless works.
What it names
A term of art for the patched-together fix that holds the system up despite being ugly — indispensable in engineering, where "it works but don’t look too closely" needs a name.
Example
The report runs on a kludge — a spreadsheet macro that quietly re-formats the export every night.
Related idea
A jury-rig is a temporary fix meant to be replaced; a kludge is often permanent precisely because it works well enough that nobody dares touch it.