attenuate

Short definition from Wiktionary

Verb

1. 1
   To reduce in size, force, value, amount, or degree.
2. 2
   To make thinner, as by physically reshaping, starving, or decaying.
3. 3
   To become thin or fine; to grow less.
4. 4
   To weaken.
5. 5
   To rarefy.
6. 6
   To reduce the virulence of a bacterium or virus.
7. 7
   To reduce the amplitude of an electrical, radio, or optical signal.
8. 8
   (of a beer) To become less dense as a result of the conversion of sugar to alcohol.

Adjective

1. 1
   Slender, thin.
2. 2
   Rarefied, thin, refined.
3. 3
   Gradually tapering into a petiole-like extension toward the base.