힘들다
himdeulda · TOPIK 1
to be hard, exhausting
🏋️ 힘들다 = 힘 (strength) + 들다 (to take, cost): it takes strength
힘 means strength or effort, and 들다 here means to be required or used up, as in 돈이 들다 (it costs money). So 힘들다 literally says strength is spent: something that drains your energy is hard and exhausting.