a person seized or held as security for the fulfilment of a condition 人质
常用词组 hold (或 take) someone hostage
seize and keep someone as a hostage 把某人持为人质
a hostage to fortune
an act, commitment, or remark which is regarded as unwise because it invites trouble or could prove difficult to live up to 招惹麻烦(或不明智、很难做到)的行为(或许诺、话语)担风险 making objectives explicit is to give a hostage to fortune. 使目的明确就要承担风险。
语源
Middle English: from Old French, based on late Latin obsidatus 'the state of being a hostage' (the earliest sense in English), from Latin obses, obsid- 'hostage'