When someone says that another person is "built like an ox," it usually means that they possess a strong and muscular physique. There are many synonyms that can be used to describe someone who is "built like an ox." For example, you could say that they are "strong as a bull," "powerful as a bear," "brawny as a gorilla," or "beefy as a buffalo." Other words that might be used to describe someone who is "built like an ox" include sturdy, robust, and well-built. Ultimately, any of these descriptions suggest a person who is physically capable and exudes a sense of strength and resilience.