Source : Webster's Revised Unabridged Dictionary (1913)

Thoroughgoing \Thor"ough*go`ing\, a.
   1. Going through, or to the end or bottom; very thorough;
      complete.

   2. Going all lengths; extreme; thoroughplaced; -- less common
      in this sense.

Source : WordNet®

thoroughgoing
     adj 1: very thorough; exhaustively complete; "an exhaustive study";
            "made a thorough search"; "thoroughgoing research"
            [syn: {exhaustive}, {thorough}]
     2: without qualification; used informally as (often pejorative)
        intensifiers; "an arrant fool"; "a complete coward"; "a
        consummate fool"; "a double-dyed villain"; "gross
        negligence"; "a perfect idiot"; "pure folly"; "what a
        sodding mess"; "stark staring mad"; "a thoroughgoing
        villain"; "utter nonsense" [syn: {arrant(a)}, {complete(a)},
         {consummate(a)}, {double-dyed(a)}, {everlasting(a)}, {gross(a)},
         {perfect(a)}, {pure(a)}, {sodding(a)}, {stark(a)}, {staring(a)},
         {thoroughgoing(a)}, {utter(a)}]