high-strung
Very nervous, tense, and easily upset or excited.
High-strung describes someone who gets nervous, tense, or excited very easily. A high-strung person might jump at sudden noises, worry intensely about small problems, or have trouble sitting still when they're anxious. Think of a tightly wound guitar string: it vibrates quickly at the slightest touch.
You might notice a high-strung friend pacing before a presentation or getting flustered when plans change unexpectedly. High-strung people often care deeply about doing things right, which can make them excellent at detail-oriented work, but their nervous energy can also exhaust them.
People sometimes confuse high-strung with high-maintenance, but they're different. High-maintenance means requiring lots of attention or special treatment. High-strung describes an internal state of tension and nervousness. A high-strung racehorse might spook at shadows, while a high-maintenance one might refuse to run unless conditions are perfect.
Being high-strung isn't necessarily bad: it can mean someone is sensitive, alert, and deeply engaged with the world around them.