Looking for an alternative to the term "rocket scientist"? Maybe you're writing a more casual piece, or maybe you're just looking for a way to add some variety to your writing. Whatever the case may be, there are plenty of expressions you can use to describe someone who's really smart or skilled. Some possibilities include "genius," "brainiac," "prodigy," "wunderkind," "whiz kid," "mastermind," "expert," "specialist," "guru," "authority," "maestro," and "virtuoso." You can also combine these words with others to create new phrases, like "math prodigy," "computer guru," or "astronomy expert." With so many options available, you'll never have to use the term "rocket scientist" again if you don't want to.