Explanation:

- Frail typically describes something that is weak, delicate, or easily broken.

- Let's explore the options for the antonym:

- Option 1: Elaborate

- "Elaborate" refers to something that is detailed or complex. It doesn't relate directly to physical strength or weakness.

- Option 2: Fancy

- "Fancy" describes something extravagant or decorative, which is unrelated to the concept of being physically strong or weak.

- Option 3: Weak

- "Weak" means lacking strength. This is a synonym, not an antonym, of "frail."

- Option 4: Robust

- Robust means strong, sturdy, and resilient, directly opposing the idea of being frail.

- This is the correct antonym for frail.