A "smart trimmer" is a personal grooming device with advanced features like long-lasting rechargeable batteries, high-performance motors, adjustable blade speeds, and often an LED display for battery life and settings. These trimmers are designed for versatile use, including styling beards, hair, and body hair, offering precision for details like creating sharp lines and close trims. Key characteristics include durable blades, multi-functional capabilities for various grooming tasks, and practical features such as a travel lock for convenient portability.