"Beefed up" is a phrase that means to make something stronger or more substantial. There are many synonyms that can be used in place of this phrase, depending on the context. For example, "strengthened," "fortified," "bolstered," or "reinforced" are all good options if you want to convey the idea of making something more robust. On the other hand, if you're looking for a word that emphasizes adding more value or importance, you might use "enhanced," "augmented," "upgraded," or "improved." Whatever your intent, there are many different words you can use to replace "beefed up" and add clarity and variety to your writing or speech.