Translation guide
The plant that cats love, or something irresistible.
The actual plant Nepeta cataria.
Common term for cat grass or catnip plant.
猫に猫草をあげた。
I gave my cat some catnip.
Loanword from English, understood by pet owners.
キャットニップのおもちゃを買った。
I bought a catnip toy.
Figurative use: something that is extremely attractive to a particular person or group.
Literally 'favorite food', used figuratively for something irresistible.
彼にとって、新しいガジェットは大好物だ。
New gadgets are like catnip to him.
When talking about the actual plant, use 猫草 or キャットニップ. For the figurative sense, Japanese doesn't have a direct equivalent, so use patterns like 大好物 or 大好き.
Simple 'loves' can convey the idea of being drawn to something.
彼女はゴシップが大好きだ。
Gossip is like catnip to her.
Proverb meaning 'like catnip to a cat', but uses silver vine (matatabi) instead.
彼にゲームの話は猫にマタタビだ。
Talking about video games is like catnip to him.