long in the tooth

Idioms and Phrases

Getting on in years, old, as in Aunt Aggie's a little long in the tooth to be helping us move . This expression alludes to a horse's gums receding with age and making the teeth appear longer. [Mid-1800s]

Example Sentences

When a TV series gets long-in-the-tooth, a little shake up can be just what it needs to survive.

From The Daily Beast