One-eyed, or having only one functioning eye, can be alternatively described as monoculated or monophthalmic. Some more colloquial synonyms include one-eyed jack and peek-eyed. Additionally, the term cyclops or cyclopean refers to a mythical creature from Greek mythology with only one eye in the middle of its forehead. One-eyed can also be used figuratively to describe someone who is narrow-minded or biased, in which case terms such as blinkered, myopic, or tunnel-visioned could be used. In any case, it's important to choose synonyms carefully as they can convey very different connotations and meanings.