rough idea
noun phraseUK /rʌf aɪˈdɪə/
US /rʌf aɪˈdiːə/
A rough idea is a simple, not-perfect plan or thought about something.
I have a rough idea of what the game will look like, but I still need to draw it.
OTHER MEANINGS
2. A first, unfinished thought about how to do something.
She gave us a rough idea of the trip before booking anything.
3. A general understanding that is not exact or detailed.
I only have a rough idea of how many people are coming.
4. An early sketch or outline used as a starting point.
The artist showed a rough idea of the poster on a napkin.