Taste:
* Sour: This is the most direct opposite in terms of taste.
* Bitter: Another strong contrast to sweet, often associated with unpleasantness.
* Salty: While not strictly opposite, saltiness contrasts with sweetness in flavor profiles.
Character:
* Mean: If "sweet" refers to a kind and gentle personality, then "mean" is its opposite.
* Cruel: This word suggests a lack of compassion, the opposite of sweetness in character.
* Unpleasant: A general term for someone or something not agreeable or pleasant.
Other meanings:
* Unsavory: This word refers to something morally questionable or distasteful.
* Unpleasant: This word can refer to anything that is not enjoyable or desirable.
To give you the most accurate opposite, please provide more context about how you are using the word "sweet."