驚愕の表情を浮かべる

The phrase combines 驚愕 (kyougaku), meaning 'surprise, astonishment, shock,' with 表情 (hyoujou), meaning 'facial expression,' and 浮かべる (ukaberu), a verb that, in this context, means 'to show, to wear (a look), to display.' 驚愕 itself is a compound word: 驚 (kyou) means 'to be surprised, to be astonished,' and 愕 (gaku) also conveys a sense of being startled or shocked. The character 驚 originally depicted a horse shying away, suggesting a sudden, involuntary reaction. 愕, on the other hand, often implies a more profound sense of shock or dismay, sometimes to the point of being dumbfounded. Therefore, 驚愕 together intensifies the meaning to a state of profound shock or astonishment. 表情 (hyoujou) is formed from 表 (hyou), meaning 'surface, outside, to express,' and 情 (jou), meaning 'feeling, emotion.' Thus, 表情 literally means 'to express feelings on the surface,' referring to how emotions manifest on the face. 浮かべる (ukaberu) has a primary meaning of 'to float,' but when used with abstract nouns like 'facial expression' or 'smile,' it takes on the meaning of bringing something to the surface, or showing it. So, '驚愕の表情を浮かべる' literally translates to 'to float/display a facial expression of profound surprise/shock.' The nuance is often that the expression is clearly visible and reflects a strong internal reaction. This phrase is commonly used in literature, news, and everyday conversation to describe a person's reaction to something unexpected, dramatic, or astonishing.