Definition
Undertaking something with the hope of success, but without any guarantee that it will happen.
碰運氣；冒險一試
He decided to go to the restaurant on spec, hoping to get a table without a reservation.
他決定碰碰運氣去餐廳，希望能沒有預訂就得到一張桌子。
I sent them my resume on spec, even though there were no vacancies, just to try my luck.
即使沒有職缺，我還是碰運氣地寄了履歷給他們。
Since we didn't book tickets in advance, we decided to go and see if we could get some last minute, just on spec.
由於我們沒有提前訂票，所以決定去碰碰運氣，看看能不能買到最後一刻的票。