English to English

verb (v)

• cause (somebody) to feel happier or more cheerful(verb.communication)

  Example:
  She tried to cheer up the disappointed child when he failed to win the spelling bee.
  

  Synonym:
  cheer, jolly along, jolly up
  

  source: wordnet30
• become cheerful(verb.communication)

  Synonym:
  cheer, chirk up
  Antonym:
  complain, kick, kvetch, plain, quetch, sound off
  

  source: wordnet30