Describes a person who is reserved, easily embarrassed, or hesitant in social situations. Often used with な to modify nouns.
He is very shy and not good at speaking in front of people.
シャイな性格だから、初対面の人とはなかなか打ち解けられない。
Because of my shy personality, I find it hard to open up to people I've just met.
He's a shy person and doesn't talk much when meeting someone for the first time.
I end up becoming shy in front of someone I like.
She's too shy to say her own opinion.