deaden

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To render less intense, sensitive, or vigorous: a medication to deaden the pain; wall tiles that deaden the sound from the rehearsal studio.
2. v. To make soundproof.
3. v. To make less colorful or brilliant.
4. v. To become dead.
5. v. To lose vigor, brilliance, or liveliness.

Century Dictionary and Cyclopedia

1. To make dead (in a figurative sense); render less sensitive, active, energetic, or forcible; impair the sensitiveness or the strength of; dull; weaken: as, to deaden sound; to deaden the force of a ball; to deaden the sensibilities.
2. To retard; hinder; lessen the velocity or momentum of: as, to deaden a ship's way (that is, to retard her progress).
3. To make impervious to sound, as a floor.
4. To make insipid, flat, or stale: said of wine or beer.
5. To deprive of gloss or brilliancy: as, to deaden gilding by a coat of size.
6. To kill; especially, to kill (trees) by girdling.

Wiktionary

1. v. transitive To render less lively; to diminish; to muffle.
2. v. intransitive To become less lively; to diminish (by itself).
3. v. transitive To make soundproof.

GNU Webster's 1913

1. v. To make as dead; to impair in vigor, force, activity, or sensation; to lessen the force or acuteness of; to blunt
2. v. To lessen the velocity or momentum of; to retard.
3. v. To make vapid or spiritless.
4. v. To deprive of gloss or brilliancy; to obscure.
5. v. To render impervious to sound, as a wall or floor; to deafen.

WordNet 3.0

1. v. lessen the momentum or velocity of
2. v. become lifeless, less lively, intense, or active; lose life, force, or vigor
3. v. make vapid or deprive of spirit
4. v. cut a girdle around so as to kill by interrupting the circulation of water and nutrients
5. v. make vague or obscure or make (an image) less visible
6. v. make less lively, intense, or vigorous; impair in vigor, force, activity, or sensation
7. v. convert (metallic mercury) into a grey powder consisting of minute globules, as by shaking with chalk or fatty oil