recherchez un mot, comme bae :
Its a combination between the words instagram and hashtag. It refers to a person that is obsessed with hashtags and writes all their comments with hashtags.
person 1: "hey have you seen the comments in Lisa's pictures, they are all hashtags"

person 2: "yes, she's a instagater
de kohaku_bambi 25 juin 2013
A person who has no life and likes to be nosey
He told you to stop instagating
de Chris 20 janvier 2005