英语释义：nervous and uncomfortable with other people
Children are often shy of/with people they don't know.
Music drew the shy girl out of her shell.
in one's shell
英语释义：often feeling uncomfortable with other people and easily embarrassed
She gave a bashful smile as he complimented her on her work.
英语释义：unwilling to be noticed or to be with other people
Joanna had a gentle retiring disposition.
He is a very quiet and retiring person.
英语释义：(especially of women) being or pretending to be shy, or like a child
She gave me a coy look from under her schoolgirl's fringe.
Coy girls often like to play cat and mouse with boys.
play cat and mouse
英语释义：shy and nervous; without much confidence; easily frightened
Kieran is a timid child.
She had a rather sheepish smile.
sheep指的是“绵羊”，含有褒义，可以指害羞而忸怩的人。而goat就常含有贬义，比如act the goat是干蠢事，old goat是老色鬼。
就像是那个经典的习语：separate the sheep from the goats（分出优劣）。
英语释义：awkward and embarrassed or ashamed
Do not be so shamefaced. You'll do it very well.
He looked somewhat shamefaced when he realized his mistake.
I couldn't see anything shameful in what I had done.
You've got nothing to be ashamed of.
She is completely shameless about her ambition.
From a merry child, then a blushing maid, she has become a perfect woman now.
I blush to think of what a fool I made of myself.