lb

Abbreviation for "like back." Most commonly seen in the comments section on celebrity Instagram accounts, put there by their delusional fans who think they can actually get a like back/get noticed. Also used by those annoying Instagram "models" in an attempt to gain new followers and/or more likes on their FitTea promotional posts.

Kardashian Fan #1: Omg! I just commented "lb" on Kylie's IG, I really hope she notices me!
Regular Person: Shut the fuck up.