the school of hard knocks

Real and practical experiences of life (as opposed to formal education), especially those involving hardship or adversity. The problem with you is that you've been spoiled your whole life. You haven't had gone through the school of hard knocks to teach you what the world is really like!

Fig. the school of life's experiences, as opposed to a formal, classroom education. I didn't go to college, but I went to the school of hard knocks. I learned everything by experience.

The practical experience of life, including hardship and disappointments. For example, A self-made man, he never went to college but came up through the school of hard knocks. This idiom uses knock, "a blow," as a metaphor for a setback. [Mid-1800s]

The school of hard knocks is that way that people learn from their experiences in life, especially from bad experiences. He graduated from the school of hard knocks as well — most of his family died in the war. All of these skills I developed in the school of hard knocks. I certainly didn't get them at university. Note: This is being contrasted with a formal academic education and the qualifications obtained by studying at a school or college. A similar phrase sometimes used is `the University of Life'.

Learning from experience, including or especially from one’s mistakes. This term comes from the nineteenth century, when advanced education was for the privileged few but many rose through the ranks of industry to considerable achievement. J. A. Froude used it in writing about politics: “The school of hard knocks. Experience teaches slowly, and at the cost of mistakes” (Short Studies on Great Subjects: Party Politics, 1850). It was more often heard from successful businessmen who had relatively little formal schooling and proclaimed quite proudly that theirs had been the “school of hard knocks.” In the 1940s and 1950s Ray Herrick, a Michigan businessman who had only a grade-school education and created a million-dollar business, would proudly announce that his alma mater was “H.N., the school of ‘hard nocks.’”