Select the most appropriate ANTONYM of the given word.

Frail

Robust

The most appropriate antonym of the word frail is robust.

• Frail means "physically weak or delicate."
• Robust means "strong and healthy; vigorous."

The other words do not have the same meaning as frail, so they are not its antonyms.

• Unreliable means "not to be trusted or depended on."
• Fresh means "having the freshness of newness or recent origin."
• Fragile means "easily broken or damaged."