Intentionally changing what the data actually show to fit a claim furthering an agenda. Anytime someone ignores, suppresses, or alters findings, results, data or statistics to fit their agenda. This could be media skewing a graph to hype fear (ex. of violent crime, drug use), politicians ignoring data needed to accurately assess a policy (ex. Lead in the water), social scientists beefing up a study's results to be published, companies claiming a product is safe (ex. Pharmaceutical clinical trials), and everyday users of Twitter who offer a "poll" to show what 'everyone' thinks.
The graph showing the increase in violent crime nationwide was obvious data gerrymandering because the statistics were only taken from the cities with populations over 1 million.
The Senator was gerrymandering data when he said that giving ex-felons the right to vote would mean all the convicted terrorists will be able to cast a ballot.
Claiming you are down to buy, hodl, and help promote a community coin cryptocurrency project, but take all your money and run the moment you get a x10. Saying you'll hold, then leaving the moment any profit happens.
The Community Coin's development team proved the project isn't a rug pull, and the value skyrocketed until some big hodlers treated it like a pump and dump scheme and did the Investor's Rug Pull. They left the developers and the community in the ditch and tanked the coin.