Definition of "clean"

(physical) Free of dirt or impurities.

1. Not dirty, filthy, or soiled.  quotations  examples

   Quotations

   • Then his sallow face brightened, for the hall had been carefully furnished, and was very clean. There was a neat hat-and-umbrella stand, and the stranger's weary feet fell soft on a good, serviceable dark-red drugget, which matched in colour the flock-paper on the walls.

     1913, Mrs. [Marie] Belloc Lowndes, chapter II, in The Lodger, London: Methuen; republished in Novels of Mystery: The Lodger; The Story of Ivy; What Really Happened, New York, N.Y.: Longmans, Green and Co., […],

2. In an unmarked condition.  examples

3. (aerodynamics) Allowing an uninterrupted flow over surfaces, without protrusions such as racks or landing gear.  examples

4. (aviation) Having the undercarriage and flaps in the up position.  examples

5. Empty.  examples

6. (of metal) Having relatively few impurities.  examples

(behavioural) Free of immorality or criminality.

1. Pure, especially morally or religiously.  quotations  examples

   Quotations

   • 1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], Psalms 51:10

   • Ah! let me knot be fool'd, sweet saints. I trust / That I am whole, and clean, and meet for Heaven.

     1833 (date written), Alfred Tennyson, “St. Simeon Stylites”, in Poems. […], volume II, London: Edward Moxon, […], published 1842, page 63

   • I do not think there is any member in this House who will not agree that that is the clean thing to do. Any member sitting on the Government benches will admit in private that that is the proper course for members who break faith.

     1914, Parliamentary Debates, volume 168, New Zealand, page 195

2. Not having used drugs or alcohol.  examples

3. (of criminal, driving, etc. records) Without restrictions or penalties, or someone having such a record.  examples

4. (informal) Not in possession of weapons or contraband such as drugs.  examples

5. (informal) Devoid of profanity.  examples

Smooth, exact, and performed well.  examples

(obsolete) Total; utter. (still in "clean sweep")  quotations

(informal) Cool or neat.  examples

(health) Being free of sexually transmitted diseases (STDs).  examples

That does not damage the environment.  examples

Free from that which is useless or injurious; without defects.  examples

Free from restraint or neglect; complete; entire.  quotations  examples

Well-proportioned; shapely.  examples

(climbing, of a route) Ascended without falling.  examples

Removal of dirt.  examples

(weightlifting) The first part of the event clean and jerk in which the weight is brought from the ground to the shoulders.  examples

(transitive) To remove dirt from a place or object.  examples

(transitive) To tidy up, make a place neat.  examples

(transitive, climbing) To remove equipment from a climbing route after it was previously lead climbed.  examples

(intransitive) To make things clean in general.  examples

(transitive, computing) To remove unnecessary files, etc. from (a directory, etc.).  examples

(intransitive, curling) To brush the ice lightly in front of a moving rock to remove any debris and ensure a correct line; less vigorous than a sweep.  examples

(manga fandom slang) To purge a raw of any blemishes caused by the scanning process such as brown tinting and poor color contrast.

(video games) Synonym of clean up  examples

To remove guts and/or scales of a butchered animal.  examples

Fully and completely.  quotations  examples

(professional wrestling slang) To defeat an opponent without using submission holds, disqualification, interference, etc. (i.e. by pinfall).