surprise (suomeksi)

yllätys (s: something not expected)
yllättää (v: cause (someone) to feel surprise / do something to (a person) that they are not expecting, as a surprise)
yllätys- (s: attributively: that is unexpected )
hämmästys (s: feeling that something unexpected has happened)
hämmästyttää (v: cause (someone) to feel surprise)