The Collaborative International Dictionary of English v.0.48:

Perficient \Per*fi"cient\, a. [L. perficiens, p. pr. of
   perficere to perform. See Perfect.]
   Making or doing thoroughly; efficient; effectual. [R.]
   --Blackstone.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Perficient \Per*fi"cient\, n.
   One who performs or perfects a work; especially, one who
   endows a charity. [R.]
   [1913 Webster]