mal de mer vs motion sickness

mal de mer and motion sickness both are nouns.

Word	Noun	Adjective	Verb	Adverb
mal de mer	Yes	No	No	No
motion sickness	Yes	No	No	No

As nouns, motion sickness is a hypernym of mal de mer; that is, motion sickness is a word with a broader meaning than mal de mer:

mal de mer: motion sickness experienced while traveling on water
motion sickness: the state of being dizzy or nauseated because of the motions that occur while traveling in or on a moving vehicle

Other hypernyms of mal de mer include kinetosis.

mal de mer (noun)	motion sickness (noun)
motion sickness experienced while traveling on water	the state of being dizzy or nauseated because of the motions that occur while traveling in or on a moving vehicle