Sometimes you might feel so happy about something you could just burst. This is the time to exult, or rejoice, and you might show your great happiness by laughing, dancing, and shouting with pure joy.
To exult means to express your joy in some visible way. Some people exult in a sedate manner, maybe just enjoying their happiness quietly within themselves. Others are more emotional, perhaps expressing their triumph in a loud or physical manner. When you break the word down into its Latin parts, the ex- means "out," and saltāre means "to leap." So exult means to leap with joy.