noun
good conductor
Technical term used in physics and engineering for materials that conduct heat, electricity, or sound well.
銅は熱の良導体です。
Copper is a good conductor of heat.
銀は電気の良導体として知られている。
Silver is known as a good conductor of electricity.
不導体 means 'nonconductor' or 'insulator', the opposite of 良導体.
Compound of 良 (good) + 導体 (conductor). A straightforward technical term.