In biblical times horses who were being trained for war had to have an essential quality before they could be used in combat. The great power of a war horse needed to be submissive to the authority of its rider. This quality of power under authority was called meekness. Being meek is not weak!
Thus, Get Wisdom! defines meekness this way:
Meekness is being willing to give up my rights in order to put others first. Meekness waits for God to bring about justice.