수줍다 and 부끄럽다 are very close in meaning, and are often used interchangeably. 1) 수줍다 (not 수좁다): shy, bashful and modest (in character and demeanor) 2) 부끄럽다: feeling embarrassment and self-consciousness (often in a particular situation) However, 부끄럽다 is also used in the sense of "ashamed" or "shameful" owing to a morally depraved action. - 그 여자아이는 수줍은 듯이 [부끄러운 듯이] 웃었다: The girl made a shy smile. - 손님들 앞이라고 너무 수줍어할 [부끄러워할] 것 없다: There's no need to be too bashful in front of the guests. - 저의 부끄러운 행동을 용서해 주십시요: Please forgive my shameful action.