Almost every word in modern dating slang describes a way of behaving badly toward someone real. Catfishing is different in kind: the person on the other end of the conversation does not exist. The photos belong to somebody else, the job is invented, the voice on the phone — if there is ever a voice — belongs to a stranger with reasons of their own.

The word arrived fully formed from a 2010 documentary, and the story inside it is worth knowing because it's almost certainly false. In the film's closing minutes, someone explains that live cod shipped from Alaska to China arrive mushy unless you put a catfish in the tank to keep them darting about. It's a lovely image for a person who keeps everyone on their toes. It is also, marine specialists say, not a thing anyone does — the anecdote traces back to a 1913 essay used as a religious allegory, revived by preachers decades later, and eventually repeated into a documentary as though it were fact. The most famous word in online deception rests on a parable.

What separates catfishing from the softer fictions people tell on dating apps is that it isn't exaggeration, it's invention — and that difference has teeth. A kittenfisher uses a flattering old photo and turns up anyway. A catfisher constructs someone who can never turn up, which is why the tells cluster: video is impossible, meeting is always next month, and — where the motive is money rather than attention, revenge or experiment — sooner or later there is a crisis that money would fix.

If that pattern is unfolding for you right now, the practical steps are unglamorous and effective. Ask for a live video call. Reverse-image-search the photos. And treat any request for money — however sympathetic the story — as the point at which you stop and verify rather than help.