(in) prep.
1. Within the bounds of; contained or included within: six rooms in the house.
2. Amidst; surrounded by: in the rain; buried in sand.
3. Within the class or group of; being a worker at, investor in, etc.: a man in a thousand; He is in munitions.
4. Occupied or concerned with: in search of truth.
5. Wearing, decorated with, etc.: that girl in blue; a room in green.
6. Made out of: I can show you this watch in gold.
7. So as to form or constitute: ornaments arranged in a spiral.
8. So as to enter into or remain within: sinking in the mud; putting his hands in his pockets.
9. As a part or function of; belonging to: We knew you had it in you.
10. According to or within the scope or range of: In my opinion you're mistaken; to come in hearing.
11. During; throughout the course of: a concert given in the evening.
12. At or before the end or expiration of: the note due in three days; I'll be there in no time.
13. With regard or respect to: Students vary in talent.
14. Affected by; under the influence of: in doubt as to the outcome.
15. By means of; with the use of: speaking in whispers; painted in water colors.
16. For the purpose of: to run in pursuit.
17. By reason or as a result of: to run in fear.
—adverb
1. To or toward the interior or inside from the exterior or outside: Please come in.
2. So as to be part of, contained by, or included with: to join in; to stir in flour.
—all in Colloq. Exhausted; worn out.
—in that Because; since: In that you're here already, you might as well stay.
—in with In association or friendship with.
—to be in for Colloq. To have the certain expectation of receiving (usually something unpleasant).
—to have it in for Colloq. To resent; bear ill will toward.
—adjective
1. That is successful; having control or authority.
2. On the inside; inner.
3. Leading or going in: the in train.
4. Colloq. a Privileged in status. b Much publicized and often admired.
5. Colloq. Understandable only to a select few: in jokes.
—noun
1. A member of a party in office or power, a team at bat, etc.
2. Colloq. A door or other means of entrance or access.
3. Colloq. Favored position or influence: an in with the boss.
4. A nook or corner.
—ins and outs
1. All the twists and turns, nooks and corners, etc.
2. The full complexities, details, etc.: the ins and outs of a question.
—v.t. inned, in·ning
1. To gather, as hay.
2. Dial. To enclose, as land. [OE]

Not; without; un–; non–. Also: i–before gn, as in ignore; il– before l, as in illiterate; im– before b, m, p, as in imbalance, immiscible, impecunious; ir– before r, as in irrefragable. [<L]
There follows a list of self–defining words with this prefix, most of them being variants of words beginning with un–. In– as here used has the meaning of “want or lack of,” “not” (as incivility, lack of civility; indevout, not devout). See the foot of this page, etc.

In; into; on; within; toward: include, incur, invade: also used intensively, as in inflame, or without perceptible force. Also il–before l, as in illuminate; im– before b, m, p, as in imbibe, immigrate, impress; ir– before r, as in irradiate. The form generally remains unassimilated in words formed in English, as in inbreed. [Fusion of IN, prep. & adverb + L in-]

In, into; within: inlet. [OE]

Chem.
Used generally to denote neutral compounds, as fats, proteins, and glycerides: stearin: sometimes spelled –ine. Also –ein. [Var. of -INE²]