If a promise is unkept, the person who made it has not done what they said they would do.

The Prime Minister has been criticized for numerous unkept promises made as part of the election campaign.

I wish I believed you, but I think this is going to be another one of your unkept promises. 但愿我能信你一回，但我认为这回你又在开空头支票了。

A garden or building that is unkept has not been cared for well.

There was a small, scrubby, unkept piece of lawn outside the house.

The garden had been unkept for many years,as he had not been well enough to take care of it. 花园多年来一直无人打理，因为他的身体不够好，无法照料它。