jargon

An obscure or technical term that's hard to understand is called jargon.

You might hear people talking about "jargon" when they're complaining about something being too complicated. That means it's using a lot of special words and phrases that only experts know, making it tough for others to follow. For example, if you're trying to fix your car but the mechanic starts explaining something with terms like "torque converter" or "ignition coil," you might think they're speaking in jargon. It's not just about using fancy language; it's about using words that are familiar only to a specific group of people, making outsiders feel left out.