thoroughgoing

/ˌθʌrəˈgoʊɪŋ/

Anything thoroughgoing is comprehensive — it pays extremely careful attention to details. Your thoroughgoing research most likely involved endless hours of sifting through multiple sources.

A thoroughgoing paint job will be neatly edged and precisely done, and a thoroughgoing government reform will involve a huge, involved overhaul of the system. This adjective has an old-fashioned sound these days, when thorough usually works just as well. Both words come from the Old English þuruh, "from end to end and side to side."

Definitions of thoroughgoing

1. adjective

   performed comprehensively and completely
   “thoroughgoing research”

   synonyms: exhaustive, thorough

   complete

   having every necessary or normal part or component or step
2. adjective

   without qualification; used informally as (often pejorative) intensifiers
   “a thoroughgoing villain”

   synonyms: arrant, complete, consummate, double-dyed, everlasting, gross, perfect, pure, sodding, staring, stark, unadulterated, utter

   unmitigated

   not diminished or moderated in intensity or severity; sometimes used as an intensifier