noun
quietness; low noise
Technical term often used in product specifications (e.g., appliances, vehicles) to describe low-noise operation or sound insulation performance.
このエアコンは静音性に優れている。
This air conditioner excels in quietness.
静音性を重視して掃除機を選ん
I chose a vacuum cleaner with an emphasis on low noise.
騒音 means 'noise' or 'unwanted sound', the opposite concept.
Compound of 静音 (quiet sound) + 性 (property, -ness). The exact historical derivation is uncertain; the term is used in modern technical contexts.