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
☆ SILENTLY; CAREFULLY Adverb 悄悄地，蹑手蹑脚地，鬼鬼祟祟地 một cách rón rén, một cách len lén, một cách lén lút