a. 乐天的, 逍遥自在的, 随遇而安的

ad. 完全偶然地

[ adj ]
cheerfully irresponsible
<adj.all>
carefree with his moneyfreewheeling urban youths
had a harum-scarum youth

Happy \Hap"py\ (h[a^]p"p[y^]), a. [Compar. {Happier}
(-p[i^]*[~e]r); superl. {Happiest}.] [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.