1 (wiktionary) 2 (vi.wikipedia) 3 (en.wikipedia) 4 (glosbe)

Core Words Familarize yourself with the 'core words'.
Compounds Expand your vocabulary by studying more complex words built by the 'core words'.
Wordsense Learn about the wordsenses of the english term.

ETYMOLOGY

KOREAN 3.0 Eng Wordtype Etym. Gb Vie
☆ VAINLY; IN VAIN; TO NO AVAIL Adverb 空然 히 无缘无故地，好端端地 vớ vẩn, lãng xẹt