'high-strung' originates from the combination of 'high' and 'strung', where 'high' indicates intensity and 'strung' refers to being tightly wound, similar to a stringed instrument.

'High-strung' evolved from the literal sense of a string being tightly wound to describe a person's tense and nervous disposition.

Initially, it referred to the physical state of being tightly wound, but over time it evolved to describe a person's emotional state.