意外
yìwài
unexpected; accident; surprise
noun/adjective
Example
这次考试的结果真是意外，我没想到会考得这么好。
Zhè cì kǎoshì de jiéguò zhēn shì yìwài, wǒ méi xiǎngdào huì kǎo de zhème hǎo.
The results of this exam were really unexpected; I didn't think I would do so well.
Can be used as both a noun meaning 'accident/surprise' and an adjective meaning 'unexpected'. Common in daily conversation when describing surprising events or outcomes.