The Collaborative International Dictionary
Decipiency
Decipiency \De*cip"i*en*cy\, n. [L. decipiens, p. pr. of
decipere. See Deceive.]
State of being deceived; hallucination. [Obs.]
--Sir T.
Browne.
Wiktionary
decipiency
n. (context obsolete English) The state of being deceived; hallucination.