a. 乐天的, 逍遥自在的, 随遇而安的
ad. 完全偶然地
在线英汉词典

happy-go-lucky的短语、例句：

happy-go-lucky adj accepting events cheerfully as they happen; carefree 乐天的; 无忧无虑的
She goes through life in a happy-go-lucky fashion. 她一向乐天知命.