Irresistible means so appealing or powerful that you can't resist it, you can't say no to it, and you can't stop yourself from wanting it or doing it. When something is irresistible, it pulls at you like a magnet.

A warm chocolate chip cookie fresh from the oven might be irresistible when you're hungry. An irresistible puppy in a pet store window makes people stop and smile, almost unable to walk past. A great book can create an irresistible urge to read just one more chapter, even when it's past bedtime.

When you feel an irresistible urge to laugh during a serious moment, you're fighting a losing battle against the giggles.

The word can describe physical things, like irresistible pizza smells, or less tangible things, like an irresistible argument that's so logical you have to agree with it. A person with an irresistible personality draws others to them naturally. Scientists might describe an irresistible force, like gravity pulling objects downward, no matter what tries to stop it.