The phrase "dead one feet" seems to be a typo or a grammatically incorrect phrase. However, assuming the intended phrase is "dead on feet," some synonyms for this phrase are exhausted, worn out, fatigued, drained, depleted, and spent. These words all describe a person who is physically and mentally tired. Other possible synonyms could include overworked, burnt out, taxed, and weakened. These words all capture the sense that someone has been pushing themselves too hard and needs rest and recuperation. Overall, there are many different words that could be used to describe someone who is "dead on their feet," depending on the context and the nuances of the situation.