A proverb literally meaning 'stupid people don't catch colds.' It is used ironically or as folk belief, suggesting that oblivious or careless people may not notice illness.
彼は熱があるのに仕事に来た。まさに『馬鹿は風邪を引かない』だね。
He came to work despite having a fever. Truly 'stupid people don't catch colds,' huh.
母は『馬鹿は風邪を引かない』と言って、体調のいい彼をからかった。
My mother teased him by saying 'stupid people don't catch colds' because he seemed fine.