스무
seumu · TOPIK 1
twenty (modifier)
스무 = 스물 (twenty) minus ㄹ, the form used right before a counter
Native Korean twenty is 스물, but it drops its final ㄹ when it modifies a counter: 스무 살 (twenty years old), 스무 개 (twenty things). Same pattern as 하나→한, 둘→두, 셋→세, 넷→네. Sound hook: seu-mu, like smooth, as in smooth at twenty.