to turn (one's face or something) downward; to tilt something face-down (transitive).
恥ずかしさのあまり、彼は顔を俯けた。
Embarrassed, he turned his face downward.
箱の中の絵を傷つけないように俯けて保管した。
They stored the picture face-down in the box to avoid damaging it.
医師は患者の頭を軽く俯けて検査を続けた。
The doctor gently tilted the patient's head downward and continued the examination.