What is a lunar eclipse on the moon?

Answer 1

A partial or total obscuring of the moon by the earth's shadow.

Are you asking "If we are on the moon, what would a lunar eclipse be?" In that case, it would be something like what we call a solar eclipse, but it would be the earth obscuring the sun. I think it might more properly be called an occultation; the earth doesn't perfectly block the sun, it literally blots it out (in the case of a total lunar eclipse) for a while until it emerges from the other edge or limb of the earth.