To decimate something such as a group of people or animals means to destroy a very large number of them.
例句
The pollution could decimate the river's thriving population of kingfishers...污染可能會造成河邊大量繁殖的翠鳥大批死亡。British forces in the Caribbean were being decimated by disease.加勒比海地區的英國部隊有大批的人病死。
VERB
嚴重削弱，大幅縮減(系統或機構)
To decimate a system or organization means to reduce its size and effectiveness greatly.
例句
...a recession which decimated the nation's manufacturing industry.使該國制造業元氣大傷的經濟衰退
英漢詞典釋義
vt.
殺死或毀滅(某物)的大部
Disease decimated the population.疾病使大批人死亡。
英英詞典釋義
Verb
1. kill one in every ten, as of mutineers in Roman armies