Gerund functioning as a noun; usually uncountable but occasionally pluralised.
Translations
The waning of public interest forced the event to be cancelled.
La décroissance de l’intérêt du public a forcé l’annulation de l’événement.
Definitions
The act or process of decreasing or declining. The waning of public interest forced the event to be cancelled.
The period or phase during which the illuminated portion of the moon is decreasing after a full moon. During the waning of the moon, the nights became progressively darker.