idea
She loves to surround herself with young people who can contribute bright new ideas.
One of my friends had the bright idea of taking a trip to the coast to enjoy the bracing sea air.
Throwing away all of my rare comic books before I went to college was not one of my brightest ideas.

SMART Vocabulary: related words and phrases

Ideas, concepts and theories
abstract
abstraction
accepted wisdom
afterthought
anthropocentrism
Darwinist
determinist
Dianetics
exceptionalism
motif
musings
natalism
non-dogmatic
non-empirical
sacred cow
social Darwinism
straw man
supersensible
tenet
the domino theory