lone hand （打牌时的）孤军奋战者，单独行动的人，单枪匹马

【例句】
When advance in a business, he albans likes to play a lone hand.
在投资时，他总爱好单枪匹马的去干。

This is a country that played a lone hand in the trade negotiations.
这是个在贸易谈判中采取单独行动的国家。