When one ditches a place so quickly, sometimes unbenounced to others, that you swiftly avoid any potential problem you may have just encountered, had you not evacuated.
Someone who is over 25 weeks into the Instagram of a person they fantasize, but will never end up with. Instaninjas must avoid liking pictures at all costs.
Guy 1: Dude, I went through that bitch's whole Instagramyesterday.
Guy 2: Bro, you're such an instaninja.