For the moon (actor muɴ- & theme) to wane.
Numpinādaw ad a''u nan būlan ti nahibihīban.
The moon was waning last night because it was the time of a two-thirds waning moon.
The following are phases of a waning moon: ay kāweng, ay uwah, nalāngad, natolbāngan, na'ipīhan, numpaddung.