Overjoyed (one word not two) means very happy.
No, the word overjoyed is not an adverb.The word overjoyed is an adjective.
overjoyed
The root word for "overjoyed" is "joy." The prefix "over-" is added to intensify the feeling of joy.
She was overjoyed to see the boy.
My dog is normally overjoyed to see me.
i was overjoyed when my team won the trophy
elated
yes
yes
· overjoyed
frantic overjoyed
overjoyed