The word “vicious” means cruel, violent, dangerous, or intentionally harmful.
In simple terms:
\[ \text{Vicious} = \text{Cruel or harmful} \]
The word “cordial” means warm, friendly, polite, and pleasant.
\[ \text{Cordial} = \text{Friendly and pleasant} \]
Since a cruel or unfriendly nature is opposite to a friendly and pleasant nature, “cordial” is the correct antonym of “vicious”.
\[ \text{Vicious} \neq \text{Cordial} \]
Explanation of the other options:
Therefore, the correct answer is: \[ \boxed{\text{Option 3 — Cordial}} \]