The term used to describe a person who talks shit and acts like a hardcore thug, gangsta, tough guy, etc., on Instagram but in real life they're the exact opposite of what they portray online.
In lamen terms: Someone who talks mad shit on social media, posting thug pictures, flossing, but when you run up on him on the streets, he's bitch made and wont man up and shoot the one, or calls the cops, or runs away or flat out cries.
Friend#1: Jake talks a lot of shit on Instagram dude, hes gonna get his ass beat one day.
Friend#2: Na man hes just an InstaThug , he dont even leave his house... EVER!!!! Guy#1: Yeah Nigga, Im in these streets son. Errrday, thugging it and fucking yo girl. Come see me if you bout that life you bitch ass nigga!!!
Guy#2: Oh word?!?!? Aight homie!!, We'll see when I see you on the block homie.
3 Days Later......
Guy#2: Wut up son!!! We outchea now homie, this is my block lets see you talk all that shit now!!!! This aint Instagram Bitch!!!!
Guy:1: Oh hey man, no I didnt mean all the shit on Instagram, it wasnt about you man, it was a joke, my shit got hacked by China... (starts to walk backwards).... Hold on im getting a call.... "hello? Hi, 911?, I need you to send a squad car, I think im going to get killed by a real thug, please help me Im on 3rd ave and 47st street".