Disappoint vs Regrettable - What's the difference?

As a verb disappoint

is to displease by eg underperforming or disappoint can be (internet slang).

of an event, action, or state, allowing or deserving regret.

To displease by e.g. underperforming

His lack of respect disappointed her.

I am disappointed by this year's revenue.

* satisfy

* disappointed adjective * disappointing adjective * disappointment noun

(head)

(Internet slang)

(en adjective)

Of an event, action, or state, allowing or deserving regret.

His painting his name of my car was more than regrettable , it was criminal.

It was regrettable that the teacher made the class retake the test when he was wrong about the answers.