'Cheerful' definitions:

Definition of 'cheerful'

(from WordNet)
adjective
Being full of or promoting cheer; having or showing good spirits; "her cheerful nature"; "a cheerful greeting"; "a cheerful room"; "as cheerful as anyone confined to a hospital bed could be" [ant: cheerless, depressing, uncheerful]
adjective
Pleasantly (even unrealistically) optimistic [syn: cheerful, pollyannaish, upbeat]

Definition of 'Cheerful'

From: GCIDE
  • Cheerful \Cheer"ful\ (ch[=e]r"f[.u]l; 277), a. Having or showing good spirits or joy; cheering; cheery; contented; happy; joyful; lively; animated; willing. [1913 Webster]
  • To entertain a cheerful disposition. --Shak. [1913 Webster]
  • The cheerful birds of sundry kind Do chant sweet music. --Spenser. [1913 Webster]
  • A cheerful confidence in the mercy of God. --Macaulay. [1913 Webster]
  • This general applause and cheerful shout. --Shak.
  • Syn: Lively; animated; gay; joyful; lightsome; gleeful; blithe; airy; sprightly; jocund; jolly; joyous; vivacious; buoyant; sunny; happy; hopeful. [1913 Webster]

Synonyms of 'cheerful'

From: Moby Thesaurus