Webster's Revised Unabridged Dictionary · 1913

Decipher

Decipher , transitive verb

[Prefix de- + cipher. Formed in imitation of French déchiffrer. See Cipher.]

1.
To translate from secret characters or ciphers into intelligible terms; as, to decipher a letter written in secret characters.
2.
To find out, so as to be able to make known the meaning of; to make out or read, as words badly written or partly obliterated; to detect; to reveal; to unfold.
3.
To stamp; to detect; to discover. [Rare]
You are both deciphered,... For villains. — Shakespeare