tumbling vs gymnastic exercise

tumbling and gymnastic exercise both are nouns.

Word	Noun	Adjective	Verb	Adverb
tumbling	Yes	No	No	No
gymnastic exercise	Yes	No	No	No

As nouns, gymnastic exercise is a hypernym of tumbling; that is, gymnastic exercise is a word with a broader meaning than tumbling:

tumbling: the gymnastic moves of an acrobat
gymnastic exercise: a sport that involves exercises intended to display strength and balance and agility

Other hypernyms of tumbling include gymnastics.

tumbling (noun)	gymnastic exercise (noun)
the gymnastic moves of an acrobat	(gymnastics) an exercise designed to develop and display strength and agility and balance (usually performed with or on some gymnastic apparatus)
	a sport that involves exercises intended to display strength and balance and agility