Concept:An antonym is a word that is opposite in meaning to the given word.
Explanation:“Audacious” means bold, daring, or fearless.
Its opposite should mean shy, fearful, or lacking courage.
Among the options, “Timid” means shy or fearful.
The other options, “Vulgar,” “Extinct,” and “Fickle,” are unrelated in meaning.
Answer:The most appropriate antonym is
Timid.