1. Portrayed as being exaggeratedly muscular, as of a person (typically male) or an image thereof. The guys in these advertisements are so beefed out that it just looks unrealistic.
2. Strengthened, updated, or improved upon in a robust way. Jenny spends a lot of time and money getting her old Ford Mustang all beefed out.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.