Simp is internet slang for a man thought to be doing too much for a woman, usually in the hope of winning her attention and usually without getting anywhere. It is used as an insult, as a joke between friends, and increasingly about almost any act of kindness.
Where it came from
It is older than the meme. Simp appeared in American slang decades ago as a shortening of simpleton, and had a run in hip hop before the internet picked it up. It took off properly around 2019 and 2020, largely through TikTok, where it broadened until it covered nearly anything.
What the insult assumes
That attention paid to a woman is a transaction, and that a man who gives more than he gets back has been cheated. That is the whole logic. It is why the word gets thrown at men who are simply being pleasant, and why plenty of people now use it ironically rather than seriously.
The version worth taking seriously is narrower: someone who is spending money or energy they cannot afford on a person who has made it clear nothing is coming back. That does happen, and it has a name of its own when money is involved.
Where it overlaps with findom
The joke version and financial domination are not the same thing. In findom, both people know exactly what the arrangement is and one of them is getting what they came for. The simp in the insult is usually the one who has not worked out there is no arrangement at all. The findom guide also covers the scams that circle that confusion.
The clearer version
Paying for someone’s time openly, as a booking, is the opposite of what the word describes: the terms are stated, the time is agreed, and nobody is hoping for something unspoken. What an escort is covers that, and the dating and hookup slang guide has the rest of the vocabulary from A to Z.