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.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
little knowledge is a dangerous thingand 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.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.