Happy, a. [Compar. Happier; superl. Happiest.]
Etymology: [From Hap chance.]
1. Favored by hap, luck, or fortune; lucky; fortunate; successful; prosperous; satisfying desire; as, a happy expedient; a happy effort; a happy venture; a happy omen. Chymists have been more happy in finding experiments than the causes of them. Boyle.
2. Experiencing the effect of favorable fortune; having the feeling arising from the consciousness of well-being or of enjoyment; enjoying good of any kind, as peace, tranquillity, comfort; contented; joyous; as, happy hours, happy thoughts. Happy is that people, whose God is the Lord. Ps. cxliv. 15. The learned is happy Nature to explore, The fool is happy that he knows no more. Pope.
3. Dexterous; ready; apt; felicitous. One gentleman is happy at a reply, another excels in a in a rejoinder. Swift. Happy family, a collection of animals of different and hostile propensities living peaceably together in one cage. Used ironically of conventional alliances of persons who are in fact mutually repugnant. -- Happy-go-lucky, trusting to hap or luck; improvident; easy-going. "Happy-go-lucky carelessness." W. Black.
Shades of meaning
Happy primarily refers to something that comes "by good hap," a chance that brings prosperity, benefit, or success.
And grasps the skirts of happy chance.
TENNYSON In Memoriam lxiii, st. 2.
In this sense happy is closely allied to fortunate and lucky. (See fortunate.) Happy has, however, so far diverged from this original sense as to apply to advantages where chance is not recognized, or is even excluded by direct reference to the divine will, when it becomes almost equivalent to blessed.
Behold, happy is the man whom God correcteth.
Job v, 17.
Happy is also applied to the ready dexterity or skill by which favorable results (usually in minor matters) are secured, when it becomes a synonym for dexterous, felicitous, and the associated words; as, he has a happy wit; happy at retort (compare clever). In its most frequent present use, happy is applied to the state of one enjoying happiness, or to that by which happiness is expressed; as, a happy heart; a happy face; happy laughter; happy tears (compare synonyms for happiness). Cheerful applies to the possession or expression of a moderate and tranquil happiness. A cheery word spontaneously gives cheer to others; a cheering word is more distinctly planned to cheer and encourage. Gay applies to an effusive and superficial happiness (often not really worthy of that name) perhaps resulting largely from abundant animal spirits: we speak of gay revelers or a gay horse. A buoyant spirit is, as it were, borne up by joy and hope. A sunny disposition has a constant tranquil brightness that irradiates all who come within its influence.
Prepositions
A happy event for him; happy at a reply; happy in his home, with his friends, among his children; happy at the discovery, over his success.