A trick or device used to attain some end.

“The box had a gimmick to make the coin appear to vanish.”

A clever ploy or strategy.

“The contest was a gimmick to get people to sign up for their mailing list.”

A gimmick capacitor.

To rig or set up with a trick or device.

“The magician's box was gimmicked with a wire that made it appear to open on its own.”