Learner's definition of CAREFUL
[more careful; most careful]
1 : using care
He is a careful driver.
You can never be too careful about these things.
Be careful! The stove is hot!
They are very careful with their money. [=they only spend what they can afford]
She was careful of their feelings.
The police were careful to leave the room exactly as they found it.
— see also (be) careful what you wish for at 1wish
2 always used before a noun : made, done, or said with care
Police made a careful examination of the scene.
We kept careful [=meticulous] records of the project.
They produced a careful study of the building.