Confound
Definition 1 of 5
Pro Tip 1/2
Unexpected Behavior
Use 'confound' when someone acts against what others predict or foresee. She confounded her critics by donating her entire fortune to charity.
Pro Tip 2/2
Sudden Surprise
Conveys a strong and often immediate feeling of surprise or disbelief. His ability to solve complex problems so quickly completely confounded me.