not known to others or the general public; obscure or unrecognized

rarely known to anyone; almost unknown or secret to all but a few

to serve as an exemplary model for others through one's own conduct and character

to have the courage to be the first to do something; to lead the way

to sacrifice one's own interest or life for the sake of others; to abandon self for others

to like to lecture others

One cannot achieve glory, wealth, or superior status without having endured the most extreme trials and tribulations; no pain, no gain.

Mao: The Unknown Story by Jung Chang and Jon Halliday

to become a father or to take on the responsibilities of a father

one who doesn't avenge an injustice is not a gentleman, one who doesn't redress a wrong is not a man

To serve the people (CCP political slogan).