When your wrist cramps after playing guitar or bass guitar for a long time becoming almost functionally useless. Typically occurs after playing fast (up tempo) music, such as death metal or thrash.
Drummer Dude: What happened to you during that last solo? You cut out.
Lead GuitarMan: The arpeggios killed me. I got wristlock and had to stop.
The time, as given by someone who doesn't have a watch and is too lazy to get their phone/other mobile device out to look.
Joe: Hey, what time is it?
Jen looks at her wrist, which has all sorts of bracelets and bangles... but no watch.
Jen: It's wrist o'clock.
Joe: Ha ha. Funny. Seriously though.
Jen: I dunno and I don't want to get my phone from my bag. Find a clock or something.