A fake or stolen online identity created or used for the purposes of beginning a deceptive relationship.

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Someone who pretends to be someone else, especially on the internet. Found on anywhere from instagram to twitter to chat sites, these people use fake pictures to disguise who they are. A synonym for this in some situations may be "troll" because the majority of catfish out there are simply out to troll others, while others have their own reasons for this approach. Often catfish, once discovered, are faced with people full of annoyance and frustration at being "catfishes"

you think you're talking to a fit bird and your actually talking to a 40-year-old obese plumber called Steve from Dorset who is wanking into a half-full bag of wotsits.

To give the impression of being an attractive person in order to attract someone online while being a complete or near opposite of that portrayed.

Catfish is someone who makes a fake account of someone on social media (Instagram, Facebook, tinder) to lure into a relationship with a false identity.

A catfish is someone who pretends to be someone they're not using Facebook or other social media to create false identities, particularly to pursue deceptive online romances.