Explanation:

- Trivial means something of little value or importance. It's often used to describe things that are insignificant or minor.

- Option 1, superficial: This is the correct synonym. It often refers to something on the surface, not deep or serious, which aligns with something being trivial.

- Option 2, warm: This refers to temperature or an attitude that is friendly or affectionate, not related to being trivial.

- Option 3, meaningful: This is the opposite in many ways, suggesting significance or importance, contrary to being trivial.

- Option 4, essential: This implies something is absolutely necessary or extremely important, which is not trivial.