I believe this to be the most ideal answer...
The Hebrew word for Pious is Chasid or Chesed.
Another translation for Chesed is 'kind'.
Jewish understanding of kindness revolves centrally around an ideal of "Ahavat Israel" - which means to be kind to [love] your fellow Jew. The natural extension of that is to be kind to any other person as well.
One method of being kind to your fellow Jew (or anyone else) would be to have peace and tolerance and understanding. That is true chesed.
Answer:
It's someone who is Torah-observant.
Einstein was always a Jew; he was not a convert. However, Einstein was never a particularly pious Jew and was something closer to a Spinozan Pantheist in terms of his spiritual orientation.
the boy is pious
The priest was a pious man who believed in divine will.The nun was not fooled by the pious expressions on the faces of the mischievous children.
He is a pious man. She is a pious woman.
The word "pious" is syllabified as pi-ous.
Bolesław the Pious was born in 1224.
He is pious, or believing in many religions.
Farshad Pious was born on 1962-01-12.
Henry II the Pious was born in 1207.
Sulpitius the Pious died on 646-01-17.
Bolesław the Pious died on 1279-04-14.
It depends on how pious they are. A religious Jew will pray three times a day at the synagogue (although two of the prayer services will be done together). Secular Jews can sometimes go years between entering a synagogue.