Meaning:

黑马 (hēimǎ) dark horse

Usage:

“黑马”原来是指在赛马场上本来不被看好，却能在比赛中出乎意料地获胜的马匹。后来比喻实力难测的竞争者或出人意料的优胜者。

“黑马(hēimǎ)” refers to the unexpected winner in a race or competition. This word is originally used in the field of horse racing.

Examples:

1. 在这次选举活动中，他一举打败了很多对手，成为了政坛黑马。

    Zài zhè cì xuǎnjǔ huódòng zhōng, tā yìjǔ dǎbài le hěnduō duìshǒu, chéngwéi le zhèngtán hēimǎ

    He had beaten all his rivals at the first try and became a dark horse in the election.

2. 真没想到，他成为了这次羽毛球赛的黑马。

    Zhēn méi xiǎngdào, tā chéngwéi le zhè cì yǔmáoqiúsài de hēimǎ.

    I didn′t expect that he became a dark horse in this match of badminton.