The waning moon.
- When the moon goes from a full moon to a crescent moon, this is an example of a time when it is waning.
- When you were extremely interested in tennis and now you are only kind of interested in tennis, this is an example of a time when your interest in tennis is waning.
- The fact or act of becoming less or less intense.
- the waning of her energy
- The fact or act of becoming smaller.
- Present participle of wane.
From wane + -ing.