The “L” stands for “loss.” Just as a sports team “takes an L” if they lose a game, someone who says they’re “taking the L” is saying they’re losing something or making a sacrifice. So if your kid tells you they’re taking the L to cram for a test, they may be sacrificing time with their friends to get a good grade.
Stay Up
If a Gen Zer is telling you to “stay up” after you’ve shared a personal problem, they’re not necessarily interested in an all-night Netflix marathon or telling you to pull an all-nighter. This term is an updated version of “chin up,” i.e., an encouraging way of telling someone they’ll be OK, and to keep going.