A more thorough explanation:

A weak trademark is a type of trademark that is descriptive or suggestive of the product or service it represents. This means that the trademark does not have a strong enough connection to the product or service to be considered distinctive. In order to receive federal protection, a trademark must be distinctive, affixed to a product that is actually sold in the marketplace, and registered with the U.S. Patent and Trademark Office.

Examples of weak trademarks include:

• "Apple" for a company that sells apples
• "Soft" for a brand of soft drinks
• "Fast" for a brand of running shoes

These examples illustrate how the trademark is not distinctive enough to be protected. The word "apple" is commonly used to describe the fruit, so it does not have a strong connection to the company that sells them. Similarly, the words "soft" and "fast" are commonly used to describe qualities of products, so they do not have a strong connection to the specific brands of soft drinks or running shoes.