indecipherable

形容词 indecipherable:

1. not easily deciphered
   同义词：unclear, undecipherable, unreadable
2. impossible to determine the meaning of

1. The coded message was indecipherable.
   这份用密码写的消息译不出来。

in.de.ci.pher.a.ble

adj.（形容词）
Impossible to decipher:
无法破译的，难以辨认的：难以辨认的或（密码等）破译不出的：
例句：
indecipherable handwriting; an indecipherable message.
难辨认的字迹；难以破译的电文

【引伸】
in.deci.pherabil.ity 或
in.deci.pherableness
n.（名词）
in.deci.pherably
adv.（副词）