Plain English Meaning
The airplane is loaded in a way that puts its balance point too far forward or too far back, making it harder and less safe to fly.
Full Definition
A loaded condition in which the aircraft's center of gravity (CG) falls outside the manufacturer's approved forward or aft limits, degrading stability, controllability, and structural safety margins.
Context Anchor
Seen in weight-and-balance planning, loading decisions, and discussions of how forward or aft loading affects aircraft handling.
Derivation
Adverse comes from the Latin adversus, meaning 'turned against' or 'unfavorable.' Here, the balance is working against rather than for them.