The saying "let
the cat out of the bag" is an English idiom simply meaning to disclose
a secret or to let a secret be known (often inadvertently).
For Example:
“It was going
to be a surprise party until someone let
the cat out of the bag”.
This is the Idiom #71 in the List of 100 commonly used Idioms in everyday English (Top 100 famous Idioms). By introducing this list of notable idioms to English learners and ESL students as you, we believe that your English will sound more like a native and you can easily understand what native speakers are saying. Please like and share this list with your friends if you think it is helpful - the full list is here.