Learner's definition of IDEA
1 [count] : a thought, plan, or suggestion about what to do
My idea is to study law.
Starting her own business seemed like a good idea at the time, but it turned out badly.
I left with the idea that I'd come back later. = I left with the idea of coming back later.
Whose idea was it to leave so early?
My idea was that if we left early we could beat the crowd.
Buying the car was a bad idea.
I have some ideas for redecorating the room.
He has an idea for a movie.
I'm not sure what to do next. Do you have any ideas?
She's always full of new ideas.
It's a good idea to talk to people who have actually been there.
There's/that's an idea! = There's/that's a good idea!
What's the next big idea in the fashion industry?
Tom has the right idea—while the rest of us are fighting traffic every day, he takes the train to work.
2 [count] : an opinion or belief
That guy has some pretty strange ideas.
“I thought he'd help us.” “What gave you that idea?”
Where did you get that idea?
I thought we could handle this ourselves, but my boss had other ideas. [=my boss did not agree]
3 : something that you imagine or picture in your mind
I formed a good idea of what the place is like by reading about it.
A hamburger and a milkshake isn't exactly my idea of a gourmet meal! [=it is not what I imagine a gourmet meal to be]
A quiet night at home is my idea of a good time.
4 [singular] : an understanding of something : knowledge about something
He has a clear idea of his responsibilities. [=he knows what his responsibilities are]
Do you have any idea of what these repairs will cost?
I have no idea what you're talking about. = I don't have the faintest/slightest idea what you're talking about. [=I do not know/understand at all what you're talking about]
“Was it hard?” “You have no idea (how hard it was)!” [=yes, it was very hard]
All right, I get the idea. [=I understand]
I think he made a mistake, but don't get the wrong idea [=don't misunderstand me], I still think he has done a good job overall.
I don't want to give you the wrong idea.
5 the idea : the central meaning or purpose of something
The whole idea [=point, object] of the game is to keep from getting caught.
The idea [=goal, aim] is to get people to attend.
I just don't get/understand the idea behind [=the reason for] this change in the rules.
(informal) Hey! What's the big idea!? [=why are you doing that?]
give someone ideasorput ideas in/into someone's head
: to cause someone to think about doing something that probably should not be done