dampen in WordNet English dictionary

1. lessen in force or effect
   "soften a shock"; "break a fall"
   dampen  damp  soften  weaken  break 
   
2. make vague or obscure or make (an image) less visible
   "muffle the message"
   dampen  deaden  damp 
   
3. deaden (a sound or noise), especially by wrapping
   muffle  mute  dull  damp  dampen  tone down 
   
4. make moist
   "The dew moistened the meadows"
   moisten  wash  dampen 
   
5. check; keep in check (a fire)
   dampen 
   
6. reduce the amplitude (of oscillations or waves)
   dampen 
   
7. smother or suppress
   "Stifle your curiosity"
   stifle  dampen