It means like back.
Usually used on instagram

Intelligence agency term for "psychological operation". A government or corporate-sponsored operation, usually taking the form of a "terrorist attack" or "crazed gunman on a spree", with the intent of panicking the public into demanding more police and laws inhibiting freedom. Psyops are usually carried out by drugging a civilian or group of civilians with aggression-promoting drugs, psyching them up, arming them, and sending them out to commit mayhem. Government-sponsored terrorism. See also blackshirts, conspiracy

LB stands for "Little Boy', commonly paired with LG for 'Little Girl'. The term was adopted and bestowed upon the youths within the Asian-Australian Community most likely due to their smaller frames. Whilst not all LB's and LG's fit this description, you may notice an LB by his 'modded' car, diamond earrings, Gucci and/or Louis Vuitton accessories, and chiselled jaw as a result of attending many Hardstyle and Trance events.

meaning "little bitch". Often used to describe whiny, complaining Noobs who are constantly bitching.

aka Little B*tch; (noun) Person who seeks eternal attention, confirmation, has a sense of entitlement and who quickly blames others for any unpleasant events which happen within their lives. Warning: extended interactions with said person will cost a large portion of your time and/or money with no gain and possibly lower your self esteem as everything will be your fault.

In a Fraternity, "LB" means "Line Brother".

Little Boy; Often used when describing a male being too cocky or Immature for his age. Hanging around older women and trying to look older for his actual age.