Describing a photograph that did not get enough light, so it came out too dark. This is the adjective — the form you use to describe the finished picture, where 'underexpose' is what the camera or the photographer did. 'These shots are underexposed' is far more common in ordinary speech than the verb. In an underexposed photo the dark parts go solid black and you lose whatever was hiding in them; faces sink into shadow. Editing software can lift some of it back, but not detail that was never recorded. The opposite is 'overexposed', a photo so bright the white parts have nothing left in them. There is a second, less common use: a person or thing that has not been seen enough by the public — 'an underexposed young writer'. Interestingly, for people 'overexposed' is the far more common word (a star we are all tired of seeing), so if you only learn one direction for people, learn that one.

曝光不足的（照片太暗）。攝影常用；形容照片本身，動詞是 underexpose。