Not defensible; not capable of being defended / Incapable of being justified or excused / Incapable of being explained

(physics) The ratio of the speed of light in air or vacuum to that in another medium.

(informal, derogatory, offensive) The act of giving something to someone under the pretense that they get to keep it permanently, and then taking it back later on, or expecting something in return.

Not destructible; incapable of decomposition or of being destroyed; invincible.

(information science) An indexing algorithm which indexes a document based on the keywords being searched for.

The inability to decide on a course of action, especially if two or more possibilities exist.

Cut in the edge into points or inequalities, like teeth; dented on the surface; jagged; notched; stamped in. / Having an irregular, uneven; sinuous; undulating.

simple past tense and past participle of indent

(military) A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these.

A subspecies of the Asian elephant, Elephas maximus indicus, distributed across India, Nepal, Bangladesh, Bhutan, Myanmar, Thailand, the Malay Peninsula, Laos, southern China, Cambodia, Vietnam, and formerly Pakistan.