Shrinking violet
/ˈʃɹɪŋkɪŋ ˈvaɪələt/
"Shrinking violet" in a Sentence (2 examples)
June, no shrinking violet she, crossed the room and introduced herself to the newcomers.
Little Johnny Jones, he was a US pilot / And no shrinking violet was he / He was mighty proud when World War III was declared / He wasn't scared, no siree!