English adjective: waning
|1.||waning (of the Moon) pertaining to the period during which the visible surface of the moon decreases|
|Samples||After full moon comes the waning moon.|
English noun: waning
|1.||waning (event) a gradual decrease in magnitude or extent|
|Samples||The waning of his enthusiasm was obvious.|
The waxing and waning of the moon.
|Broader (hypernym)||decrease, drop-off, lessening|