Defeat means getting beaten, or failing at doing something. Stunning in this case means that what happened was so bad that you couldn't figure out what to do next, that everything just came to a stop.
I suffered defeat at the hands of my opponent.
Germany
Waterloo
'Stunning ' is mind blowing.
Charleston, South Carolina
Charleston
He suffered a major military defeat at Waterloo.
The army suffered a stinging defeat in their war with Britian.
the first battle of bull run
It can mean beautiful
The Balkans led successful campaigns against the ottomans and rebels. This took place in the Netherlands, but suffered a disastrous defeat against the English.
japan