The phrase "am big" may seem simple enough, but it actually has many different synonyms that can be used to describe someone's size or importance. Some common synonyms for "am big" might include "am sizable," "am significant," "am substantial," "am massive," "am grand," "am mighty," "am substantial," and "am imposing." In addition to these synonyms, there are also more specific words that can be used to describe someone's size or importance, such as "am colossal," "am gargantuan," "am prodigious," and "am formidable." No matter what synonyms you use to describe someone's size or importance, it's important to choose words that accurately portray the person or object in question.