noun
nonconductor; insulator
Technical term in physics and engineering for a material that does not readily conduct heat or electricity.
ガラスは電気の不導体として使われる。
Glass is used as an electrical nonconductor.
導体 means conductor (of heat or electricity), the opposite of 不導体.
Compound of 不 (fu, 'non-') + 導 (dō, 'conduct') + 体 (tai, 'body'). The exact historical derivation is uncertain, but the word follows standard Sino-Japanese word formation patterns.