literary A person who knows a little about something may think he knows it all and make bad mistakes. A proverb. John has read a book on driving a car and now he thinks he can drive. A little knowledge is a dangerous thing.
A LITTLE KNOWLEDGE IS A DANGEROUS THING
Meaning of A LITTLE KNOWLEDGE IS A DANGEROUS THING in English
American idioms English vocabulary. Английский словарь американских идиом. 2012