be long in the tooth

To be old. Animals' teeth, especially those of horses, are thought to be an indicator of age. As animals age, their gums recede, and their teeth look longer. Our poor cat is so long in the tooth that he struggles just walking around the house these days. She's a little long in the tooth to still be working—do you think she'll ever retire?

be long in the tooth

(humorous)

to be too old

Usage notes: The older a horse is, the longer its teeth are.

I'd have thought she was a bit long in the tooth to be starring as the romantic heroine.

Common Names:

Name	Pronounced	Usage
Livvy	-	English
Sibonakaliso	-	Southern African, Zulu
Elouise	EL-o-eez, el-o-EEZ	English
Dragos	-	Romanian
Euphrosyne	-	Greek Mythology
Prunella	proo-NEL-ə	English (Rare)