little knowledge is a dangerous thing

a little knowledge is a dangerous thing

proverb Having a precursory or limited amount of knowledge about something can make one overestimate how well they will be able to do something much larger in scope or scale. Just because she painted her room by herself, now she thinks she can do the entire house—inside and out! A little knowledge is a dangerous thing, I tell you.
See also: dangerous, knowledge, little, thing
Farlex Dictionary of Idioms.

little knowledge is a dangerous thing

 and little learning is a dangerous thing
Prov. Cliché If you only know a little about something, you may feel you are qualified to make judgments when, in fact, you are not. After Bill read one book on the history of Venezuela, he felt he was an authority on the subject, but he wound up looking like a fool in discussions with people who knew a lot more about it than he did. A little learning is a dangerous thing.
See also: dangerous, knowledge, little, thing
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • a little knowledge is a dangerous thing
  • a little learning is a dangerous thing
  • a bird in hand
  • a bird in the hand
  • a straw will show which way the wind blows
  • a/the feel of (something)
  • a bird in the hand is worth two in the bush
  • a slew of (something)
  • (one) could use (something)
  • a slue of (something)
References in periodicals archive
HAVING read the letter (June 9) written by Jon Haddy, who is also the secretary of the Llangollen Plaid Cymru branch, I was reminded of the old adage "a little knowledge is a dangerous thing".
While this transformation has generally been lauded in postindustrial societies like Great Britain and the United States, it has left many people - and countries - out in the cold, Neef suggests in A Little Knowledge Is a Dangerous Thing.
Source: A Little Knowledge Is a Dangerous Thing: Understanding Our Global Knowledge Economy by Dale Neef.