Source : Webster's Revised Unabridged Dictionary (1913)

Implead \Im*plead"\, v. i.
   To sue at law.

Implead \Im*plead"\, v. t. [imp. & p. p. {Impleaded}; p. pr. &
   vb. n. {Impleading}.] [Cf. {Emplead}.] (Law)
   To institute and prosecute a suit against, in court; to sue
   or prosecute at law; hence, to accuse; to impeach.