brainstorm

US /ˈbreɪn.stɔːrm/
UK /ˈbreɪn.stɔːrm/
1.

(of a group of people) to suggest a lot of ideas for a future activity very quickly, before considering some of them more carefully:

:
The team got together to brainstorm.
1.

a sudden smart idea:

:
The toy's inventor was watching his children play one day when he had a brainstorm.