thorough

Etymology

From Middle English thoruȝ, þoruȝ, from Old English þuruh, a byform of Old English þurh, whence comes English through. The adjective derives from the preposition and adverb. The word developed a syllabic form in cases where the word was fully stressed: when it was used as an adverb, adjective, or noun, and less commonly when used as a preposition.

adj

1. Painstaking and careful not to miss or omit any detail.
   The Prime Minister announced a thorough investigation into the death of a father of two in police custody.
   He is the most thorough worker I have ever seen.
   The infested house needs a thorough cleansing before it will be inhabitable.
2. Utter; complete; absolute.
   I was elected to the Executive Committee of the Vegetarian Society, and made it a point to attend every one of its meetings, but I always felt tongue-tied. Dr. Oldfield once said to me, 'You talk to me quite all right, but why is it that you never open your lips at a committee meeting? You are a drone.' I appreciated the banter. The bees are ever busy, the drone is a thorough idler. And it was not a little curious that whilst others expressed their opinions at these meetings, I sat quite silent. Not that I never felt tempted to speak. But I was at a loss to know how to express myself. All the rest of the members appeared to me to be better informed than I. Then it often happened that just when I had mustered up courage to speak, a fresh subject would be started. This went on for a long time. 1925-29, Mahadev Desai (translator), M.K. Gandhi, The Story of My Experiments with Truth, Part I, chapter xviii

prep

1. (obsolete) Through.

noun

1. (UK, dialect) A furrow between two ridges, to drain off the surface water.
   The Ignorance and Idleness of the Plowman, who either goes so shallow, or plows his Thoroughs so wide, or misses Part of the Ground. 1733, William Ellis, Chiltern And Vale Farming Explained