What is the Greek word for certain?

There isn't one single perfect Greek word for "certain" because the meaning can vary depending on the context. However, here are a few options with slightly different nuances:

* βεβαίος (bebaios): This is a good general option, implying something is sure, reliable, and beyond doubt. It's often used for certainty about facts or events.

* σίγουρος (sigouros): This word is closer to the colloquial English "sure" or "confident," implying a strong belief but perhaps not absolute, irrefutable proof.

* απόλυτος (apolytos): This means "absolute" or "unconditional," suggesting a certainty that leaves no room for doubt or exception.

The best choice will depend on the specific sentence and the type of certainty being expressed.