すた廃sutaれるreru
1.
To gradually lose popularity or relevance over time, becoming less practiced or acknowledged within a society or culture.
2.
To experience a decline in vibrancy or status, often resulting in the disappearance of once-thriving customs, practices, or entities.
3.
To fall out of favor or usage due to changing societal trends, leading to obsolescence or neglect of particular items, practices, or ideas.
4.
To lose its previously held dignity or prestige, often implying a tarnishing of reputation as a result of diminished significance or value.
Example:
その風習はすたれつつある。