1. superlative form of buff; most muscular or physically fit
Usage: informal; often used to describe someone with well-developed muscles
2. superlative form of buff; most enthusiastic or knowledgeable about a particular subject
Usage: informal; used to describe the biggest fan or expert

Examples

• He's the buffiest guy at the gym after months of intense training.
• She's the buffiest Marvel fan I know—she's seen every movie multiple times.
• The buffiest members of the team always lead the workouts.
• He became the buffiest version of himself by following a strict diet and exercise plan.
• Among all the history buffs in the club, she's definitely the buffiest.