efficious

Etymology
Possibly a variation of efficacious or derivative of efficacy influenced by analysis of the final -c- in the later word as being part of a suffix -cy rather than the word-stem.

Adjective

 * 1)  Efficacious.
 * 2) * 1899, The Carolina Medical Journal, volumes 43-44, page 207, quoting the Medical Standard:
 * This remedy will be found speedily efficious in hoarseness due to excessive action of the vocal cords or resulting from an acute cold.
 * This remedy will be found speedily efficious in hoarseness due to excessive action of the vocal cords or resulting from an acute cold.