impregnable im'pregnәbl
GRE
释义
a. 无法攻取的, 坚强不屈的, 驳不倒的
英文释义
s. immune to attack; incapable of being tampered with
s. incapable of being overcome, challenged or refuted
BNC词频排名: 19,132 | 当代语料库词频排名: 25,486