Waning

verb (used without object), waned, waning.
1.
to decrease in strength, intensity, etc.:
Daylight waned, and night came on. Her enthusiasm for the cause is waning.
2.
to decline in power, importance, prosperity, etc.:
Colonialism began to wane after World War II.
3.
to draw to a close; approach an end:
Summer is waning.
4.
(of the moon) to decrease periodically in the extent of its illuminated portion after the full moon.
Compare wax2 (def 2).
noun
5.
a gradual decrease or decline in strength, intensity, power, etc.
6.
the drawing to a close of life, an era, a period, etc.
7.
the waning of the moon.
8.
a period of waning.
9.
a defect in a plank or board characterized by bark or insufficient wood at a corner or along an edge, due to the curvature of the log.
Idioms
10.
on the wane, decreasing; diminishing:
The popularity of that song is on the wane.
verb (intransitive)
1.
(of the moon) to show a gradually decreasing portion of illuminated surface, between full moon and new moon Compare wax2 (sense 2)
2.
to decrease gradually in size, strength, power, etc
3.
to draw to a close
noun
4.
a decrease, as in size, strength, power, etc
5.
the period during which the moon wanes
6.
the act or an instance of drawing to a close
7.
a rounded surface or defective edge of a plank, where the bark was
8.
on the wane, in a state of decline
see: wax and wane