I prefer "habitability" over either term. "This place is a mess, we're constantly tripping over things, how about we make it a more habitable codebase to work in?"
No matter what you call it, though, if teams aren't empowered/encouraged to make the code more habitable, it won't happen. You could call it "partying" instead of "removing tech debt" and folks still won't do it if the system around them discourages it ("must work on next feature now!").