cheer in WordNet English dictionary

1. spur on or encourage especially by cheers and shouts
   "The crowd cheered the demonstrating strikers"
   cheer  root on  inspire  urge  barrack  urge on  exhort  pep up 
   
2. become cheerful
   cheer  cheer up  chirk up 
   
3. show approval or good wishes by shouting
   "everybody cheered the birthday boy"
   cheer 
   
4. cause (somebody) to feel happier or more cheerful
   "She tried to cheer up the disappointed child when he failed to win the spelling bee"
   cheer  cheer up  jolly along  jolly up 
   
5. give encouragement to
   cheer  hearten  recreate  embolden 
   

1. the quality of being cheerful and dispelling gloom
   "flowers added a note of cheerfulness to the drab room"
   cheerfulness  cheer  sunniness  sunshine 
   
2. a cry or shout of approval
   cheer