Decay is the process or result of deteriorating in condition, of being gradually decomposed.
- You have the Pyrrhic dance as yet,
Where is the Pyrrhic phalanx gone?
Of two such lessons, why forget
The nobler and the manlier one?
You have the letters Cadmus gave—
Think ye he meant them for a slave?
- A gilded halo hovering round decay.
- Lord Byron, The Giaour (1813), line 100.
- The ripest fruit first falls, and so doth he;
His time is spent.
- As is the bud bit with an envious worm,
Ere he can spread his sweet leaves to the air,
Or dedicate his beauty to the sun.
- In the sweetest bud
The eating canker dwells.
- Fires that shook me once, but now to silent ashes fall'n away.
Cold upon the dead volcano sleeps the gleam of dying day.
- Alfred Tennyson, Locksley Hall Sixty Years After (1886), Stanza 21.
Hoyt's New Cyclopedia Of Practical Quotations 
- Quotes reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 181-82.
- He that loves a rosy cheek,
Or a coral lip admires,
Or from star-like eyes doth seek
Fuel to maintain his fires;—
As old Time makes these decay,
So his flames must waste away.
- Thomas Carew, Disdain Returned.
- A worm is in the bud of youth,
And at the root of age.
- William Cowper, Stanzas Subjoined to a Bill of Mortality.
- An age that melts with unperceiv'd decay,
And glides in modest innocence away.
- Samuel Johnson, Vanity of Human Wishes, line 293.
- There seems to be a constant decay of all our ideas; even of those which are struck deepest, and in minds the most retentive, so that if they be not sometimes renewed by repeated exercises of the senses, or reflection on those kinds of objects which at first occasioned them, the print wears out, and at last there remains nothing to be seen.
- John Locke, Human Understanding, Book II, Chapter 10.
- All that's bright must fade,—
The brightest still the fleetest;
All that's sweet was made
But to be lost when sweetest.
- Thomas Moore, National Airs, Indian Air.
- I shall be like that tree,—I shall die at the top.
- Jonathan Swift, Scott's Life of Swift.