dampen - verb

• smother or suppress
• make moist
• deaden (a sound or noise), especially by wrapping
• reduce the amplitude (of oscillations or waves)
• make vague or obscure or make (an image) less visible
• check; keep in check (a fire)
• lessen in force or effect

dampen - thesaurus

break   damp   deaden   dull   moisten   muffle   mute   soften   stifle   wash   weaken