Plain English Meaning
The airplane rolls on its own, without the pilot asking it to. One wing drops because it has stopped flying properly, and the airplane tips toward that side even though the pilot did not turn the control wheel.
Full Definition
A roll of the airplane about its longitudinal axis that occurs without the pilot moving the ailerons to cause it. In the stall context, it typically results from one wing stalling before the other, causing that wing to drop suddenly while the opposite wing continues producing lift.
Context Anchor
Encountered during stall recognition and recovery, especially when noticing that the airplane may not remain wings-level as the stall develops.
Derivation
‘Uncommanded’ means ‘not ordered’ — from the Latin ‘mandare’ (to order or entrust). In flying, it signals that the airplane is doing something the pilot did not tell it to do, which is always worth paying to.