天てん敵てき

noun

natural enemy; predator; archenemy

Refers to a creature that preys on or is the natural opponent of another species. Also used figuratively for a person or thing that one is inherently weak against or incompatible with.

• カマキリはバッタの天てん敵てきだ。

  The praying mantis is a natural enemy of the grasshopper.

• 彼かれにとって、甘あまいものはダイエットの天てん敵てきだ。

  For him, sweets are the archenemy of his diet.