Meaning of “stale” - Learner’s Dictionary

stale

adjective uk us /steɪl/
OLD

old and not fresh:

stale bread
Cake goes stale quickly if it's not covered.
BORING

boring or bored, and not producing or feeling excitement or enthusiasm like before:

After 21 years their marriage had begun to go stale.
I'd been too long in the same job and was getting stale.

(Definition of “stale” from the Cambridge Learner’s Dictionary © Cambridge University Press)