Dispersion \Dis*per"sion\, n. [CF. F. dispersion.]

1. The act or process of scattering or dispersing, or the state of being scattered or separated; as, the Jews in their dispersion retained their rites and ceremonies; a great dispersion of the human family took place at the building of Babel.

The days of your slaughter and of your dispersions are accomplished. --Jer. xxv. 34.

2. (Opt.) The separation of light into its different colored rays, arising from their different refrangibilities.

Dispersion of the optic axes (Crystallog.), the separation of the optic axes in biaxial crystals, due to the fact that the axial angle has different values for the different colors of the spectrum.

Source: Webster's Revised Unabridged Dictionary (1913)

The CORRECT word is:-

Noun: aspersion u'spurzhun

1. A disparaging remark
"in the 19th century any reference to female sexuality was considered a vile aspersion"
- slur

2. An abusive attack on a person's character or good name
- calumny, slander, defamation, denigration

3. The act of sprinkling water in baptism (rare)
- sprinkling

Derived forms: aspersions

See also: asperse

Type of: attack, baptism, depreciation, derogation, disparagement

Encyclopedia: Aspersion

And then:-
"I know about the admonition against casting pearls of wisdom among swine, lest they turn upon me-as rabid dogs- and attempt to tear me assunder!"

When it should be:
a·sun·der (-sndr)
adv.
1. Into separate parts or pieces: broken asunder.
2. Apart from each other either in position or in direction: The curtains had been drawn asunder.
[Middle English, from Old English on sundran : on, on; see on + sundran, separately (from sunder, apart).]
a·sunder adj.
The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2003. Published by Houghton Mifflin Company. All rights reserved.