Definition & Meaning of "[blow] {one's} cover"

What is the origin of the idiom "blow one's cover" and when to use it?

The idiom "blow one's cover" originated from espionage and undercover operations, particularly in the context of spy activities. It is used to refer to the unintentional or deliberate exposure of a covert identity or secret operation, jeopardizing the individual's ability to maintain their disguise or remain undetected.