Source : Webster's Revised Unabridged Dictionary (1913)

Non-pros \Non`-pros"\, v. t. [imp. & p. p. {Nonprossed}; p. pr.
   & vb. n. {Non-prossing}.]
   To decline or fail to prosecute; to allow to be dropped (said
   of a suit); to enter judgment against (a plaintiff who fails
   to prosecute); as, the plaintiff was non-prossed.