adverb
for many years; anciently
Archaic or highly literary adverb meaning 'for a long time' or 'since ancient times'. Not used in everyday speech; encountered mainly in classical texts or poetic language.
年久しくこの地に住み着いた民の話が伝わっている。
A tale has been passed down of people who settled in this land many years ago.
年久しく語り継がれてきた伝説を、今も村人は覚えている。
The villagers still remember the legend that has been told for many years.