also: せいねこ
noun
adult cat; fully-grown cat
Refers to a cat that has reached maturity, typically over one year old. Used in veterinary, breeding, or everyday contexts.
この保護施設には成猫がたくさんいます。
There are many adult cats at this shelter.
子猫と成猫では必要な栄養が違います。
The nutritional needs of kittens and adult cats are different.
Compound of 成 (sei, 'become' or 'adult') and 猫 (byō/neko, 'cat'). The reading せいびょう uses the on'yomi for both characters, while せいねこ mixes on'yomi and kun'yomi.