Definition of "inkstain"

He was shabby and careless, with inkstains on the sleeves of his jacket, and his cravat was large and billowy, under a chin shaped like the toe of an old boot.

1899 February, Joseph Conrad, “The Heart of Darkness”, in Blackwood’s Edinburgh Magazine, volume CLXV, number M, New York, N.Y.: The Leonard Scott Publishing Company, […], part I, page 200

She noticed, too, an inkstain on his right forefinger and judged that the daily grind of theme-correction was going on in spite of everything.-Cope, flushed and now rather tired, walked up stairs with his photographs, took a perfunctory sip from a medicine-glass, looked at the inkstain on his finger, and sat down at his table. Two or three sheets of a letter were lying on it, and he re-read a paragraph or so before dipping his pen.

1919, Henry Blake Fuller, chapter 15, in Bertram Cope's Year