as an adjective, "pleased, happy," 1860, British dialect, from obsolete chuff "swollen with fat" (1520s). A second British dialectal chuff has an opposite meaning, "displeased, gruff" (1832), from chuff "rude fellow," or, as Johnson has it, "a coarse, fat-headed, blunt clown" (mid-15c.), which is of unknown origin. Related: Chuffed "pleased" (1957).
early 15c., "supreme happiness," from French béatitude (15c.) and directly from Latin beatitudinem (nominative beatitudo) "state of blessedness," from past participle stem of beare "make happy" (see Beatrice). Attested from 1520s as "a declaration of blessedness" (usually plural, beatitudes, especially in reference to the Sermon on the Mount).
No cognates outside Germanic. "The earlier application was to the outward expression of kindly feeling, sympathy, affection to others, as in Gothic and ON.; but in OE. the word had come more usually to be applied to the external manifestation of one's own pleased or happy frame of mind, and hence even to the state itself" [OED]. Rare since 16c.
pictorial character, by 2008, from Japanese e "picture" + moji "character" (compare kanji), coined 1999 in Japanese by Shigetaka Kurita, NTT DoCoMo employee. Its adoption in English was driven by Apple iPhone's inclusion of the feature in 2008. The similarity to native emoticon is a happy coincidence.