If a jury or judge were to decide whether your design practices fair use of trademark, they would look whether your design is a:
- Descriptive fair-use
Some trademarks come with descriptive meaning. Also, their secondary meaning is marked as a trademark work. Let’s take the example of Apple. Even though it's a registered trademark, its descriptive sense denotes the fruit.
- Nominative fair use
It’s when somebody uses a trademark to identify a product or service or the owner of the trademark. For example, you want to create and sell a t-shirt that has text like — “I Don’t Like ABC Company.” You cannot use the trademark ABC in your design if you’re actually using it to refer to ABC brand.
Your design shouldn't create any confusion for descriptive as well as nominative fair uses while uploading on the marketplace. In simple words, think from a consumer’s perspective whether your design is sold or allowed by the trademark owner.
Fair use is actually a confusing topic. One person's fair use might end up being other's unfair use. In case you think that your design is a fair use or if you aren't sure if it violates other's rights, consult an attorney.
Remember, the court of law is the only place to decide fair use.