waning

adj. diminishing (moon); declining; ebbing, subsiding, dwindling; approaching the end (of life, a period, etc.)

v. diminish; decline; ebb, subside, dwindle; approach the end (of life, a period, etc.)

Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. The lunar phases vary cyclically as the Moon orbits the Earth, according to the changing geometry of the Earth, Moon, and Sun. One half of the lunar surface is always illuminated by the Sun (except during lunar eclipses), and is hence bright, but the portion of the illuminated hemisphere that is visible to an observer can vary from 100% (full moon) to 0% (new moon). The boundary between the illuminated and unilluminated hemispheres is called the terminator.
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Noun
1. a gradual decrease in magnitude or extent; "the waning of his enthusiasm was obvious"; "the waxing and waning of the moon"
(antonym) waxing
(hypernym) decrease, lessening, drop-off
(derivation) decline, go down, wane
Adjective
1. (of the moon) pertaining to the period during which the visible surface of the moon decreases; "after full moon comes the waning moon"
(antonym) waxing

Noun
1. a gradual decline (in size or strength or power or number)
(synonym) ebb, ebbing
(hypernym) decline, diminution
(derivation) decline, go down
Verb
1. grow smaller; "Interest in the project waned"
(synonym) decline, go down
(hypernym) decrease, diminish, lessen, fall
(hyponym) dip
(derivation) ebb, ebbing
2. become smaller; "Interest in his novels waned"
(antonym) wax, mount, climb, rise
(hypernym) decrease, diminish, lessen, fall
(derivation) waning
3. decrease in phase; "the moon is waning"
(antonym) wax, full
(hypernym) decrease, diminish, lessen, fall
(derivation) ebb, ebbing

(p. pr. & vb. n.)
of Wane
  

(n.)
The act or process of waning, or decreasing.
  

      awning