Often preceded by the terms ‘moral’ or ‘free’ in LDS discourse, agency connotes free will, the moral and intellectual capacity to make choices, and accountability. It is central to God’s plan for making humans more like God. Satan, or the adversary, is described as attempting to ‘destroy’ human agency, and to the extent we attempt to unrighteously coerce or compel our fellow human beings, we are also opposing the work of God.

Wherefore, because that Satan rebelled against me, and sought to destroy the agency of man, which I, the Lord God, had given him, and also, that I should give unto him mine own power; by the power of mine Only Begotten, I caused that he should be cast down.
Moses 4:3
And it came to pass that Adam, being tempted of the devil—for, behold, the devil was before Adam, for he rebelled against me, saying, Give me thine honor, which is my power; and also a third part of the hosts of heaven turned he away from me because of their agency.
Doctrine and Covenants 29:36
We have learned by sad experience that it is the nature and disposition of almost all men, as soon as they get a little authority, as they suppose, they will immediately begin to exercise unrighteous dominion. Hence many are called, but few are chosen. No power or influence can or ought to be maintained by virtue of the priesthood, only by persuasion, by long-suffering, by gentleness and meekness, and by love unfeigned.
Doctrine and Covenants 121:39-41