出典:Wiktionary
surprize (countable かつ uncountable, 複数形 surprizes)
surprize (三人称単数 現在形 surprizes, 現在分詞 surprizing, 過去形および過去分詞形 surprized)
The z spelling was as common as the s spelling into the early 1700s, but has been rare ever since, and is now nonstandard.