What is the Sino-Korean word for "seasickness"?

 ANSWER: 선훈 (船暈)

The pure Korean word for "seasickness" is 배멀미, which literally means "boat (배) nausea (멀미)," but the Sino-Korean word is 선훈 (船暈), which literally means "boat (船) dizziness (暈)." Interestingly, at least to me, the Chinese word for "seasickness" is 暈船 (훈선), which literally means "dizzy (暈) boat (船)." The character 暈 (훈) can also mean "halo."

By the way, there are not many Korean words that start with 섣, which is pronounced with a long vowel sound, so /서어ㄷ/.