Do you know the etymology of this word?

My mother tongue is Japanese.

Ex post facto law refers to punishing an act with a law that was enacted after the act became a crime.

People from all over the country gathered to celebrate the emperor's birth.

He is learning Icelandic.

That personage is a famous figure in this town.

I am thinking of a strategy to solve this problem.

I entered the new library for the first time.

He can speak Urdu fluently.

An old person was walking in the park.