Comprehensive resource for understanding and mastering English idioms
The idiom "nail biter" refers to a person who is very anxious or nervous before an event or situation that may affect them greatly, such as a performance or a test. It comes from the idea of biting one's nails nervously or anxiously.
The earliest known use of the idiom "nail biter" was in 1603, according to the Oxford English Dictionary. It comes from Old English "bite", which means "to gnaw". The idea of biting one's nails nervously or anxiously became a common way to describe someone who is very anxious or nervous before an event or situation that may affect them greatly. Over time, the idiom has become more commonly used to describe people in general who are very anxious or nervous about something.