(of food) no longer fresh and pleasant to eat; hard, musty, or dry:stale bread no longer new and interesting or exciting:their marriage had gone stale [predic.] (of a person) no longer able to perform well or creatively because of having done something for too long:a top executive tends to get stale (of a cheque or legal claim) invalid because out of date: justifications for adverse possession go beyond stale claims
make or become stale: [no object]:she would cut up yesterday’s leftover bread, staling now