At a basic level, meekness is open-mindedness, gentleness and self-control. At a higher level, it means emptying oneself of personal will, and overcoming many fears, including fear of criticism. It means surrendering an over-inflated confidence in our own judgement. Meek people have none of these embarrassments.
They know meekness is strength, restrained by love. Only strong people (not in muscle, but in mind) can be meek. The meek don't think less of themselves, but they think of themselves less. They exhibit strength without compromise, shown by putting others' needs before their own.
And what is the earth they are to inherit? It's not acreage. "Inheriting the earth" means having a power over human hearts that others do not possess.
Helen Keller had this power. She defined meekness this way. "I long to accomplish a great and noble task, but my chief duty is to accomplish small tasks as if they were great and noble."