What is the Latin root word for responsible?

The Latin root word for "responsible" is spondere, which means "to promise".

Here's how it works:

* spondere (to promise) + -able (capable of) = sponsible

* sponsible then evolved into responsible, where the "s" was added for phonetic reasons.

Therefore, "responsible" literally means "capable of promising". It implies a sense of obligation and accountability for one's actions and commitments.