expression
Archaic phrase equivalent to modern めでたい; used in classical or formulaic contexts, especially in the set phrase めでたしめでたし ('and they lived happily ever after').
See also: 目出度い (めでたい)
At the end of old tales, it says 'and they lived happily ever after'.
この婚礼はまことにめでたし。
This wedding is truly auspicious.