The phrase "tower over" means to be much taller or larger than something or someone else. Some synonyms for "tower over" include loom, overshadow, dwarf, dominate, and surpass. Loom implies a threatening or intimidating presence, while overshadow suggests casting a shadow over something or someone. Dwarf suggests being significantly smaller than something else, while dominate implies having power or control over something or someone. Finally, surpass suggests exceeding expectations or being superior to something or someone else. All of these words can be used interchangeably with "tower over" to describe someone or something that is much bigger or more powerful than others.