Can you hit the ball on the full in table tennis?

Answer 1

Generally, no.

If you "volley" the ball (as they do in tennis), you would lose the point.

The technical term is "obstruction" but what it refers to is hitting the ball before it bounces.

If there's a chance that the ball might hit the table because it's still travelling towards it, your opponent would lose the point if he prevented it from doing so by hitting/volleying it on the full.

But ...

If the ball has already passed over the table and/or is travelling away from the table, your opponent wins the point whether he hits/volleys it or not.

And also ... as well as hitting the ball with your racket, if you touch the ball with any part of your body or with anything you carry, the same rule applies.