rearguard /ˈriɚˌgɑɚd/ adjective Learner's definition of REARGUARD
always used before a noun
: fought or conducted by a group of soldiers at the rear of an army especially during a retreat(尤指撤退中)后卫部队进行的 —
often used figuratively to describe an effort or fight to change or stop something that is very close to happening or being done常用作比喻,形容防止某事发生的努力或抗争