How do you say spy in Japanese?
— 間諜 (かんちょう, kanchō); スパイ (supai)

Specialized synonyms for spy in Japanese
moleモグラ (mogura)
shadow影 (kage), 陰影 (いんえい, in'ei)
tail尻尾 (しっぽ, shippo); しっぽ (shippo); 尾 (お, o)