Drunk; by drinking gin or other alcoholic drink. Alternatively; enlivened.
Gin has been used as a verb with several meanings:
- To start - clearly a synonym of 'begin'. This is old and is cited in Wycliffe's Bible, 1382:
"Heere gynneth the prologe in the boc of Ecclesiastes. Ibid. i. heading, Heer gynneth the booc."
- To catch (in a trap). Also old, as seen here in John Fletcher's, The Nice Valour, 1625:
"So, so, the Wood~cock's gin'd; Keep this doore fast, brother."
- To give. This seems to be just a southern US pronunciation of 'give'. In use since at least 1844, as here from the Ohio newspaper The Lorain Republican, from April that year:
"He paid me my half and I gin him up the note."
- To remove the seeds of cotton from. From the Transactions of the Society of Arts, 1789:
"It is the easiest of all Cotton to gin."
- To excite or enliven - to make work hard. This may be a form of, or precursor to, 'ginger up'. Francis Francis Junior's, Saddle & Mocassin, 1887, has:
"The Apaches were out to beat hell - And they were ginning her up, and making things a bit lively, that's a fact!"
- To drink liquor, especially gin.
From the Helena Independent, 1881:
In New England when a man is drunk he is "on a tool," in Chicago he is "on a hoorah," in St Louis he "has a dash too much up his nose," in Kansas City he is "ginned up for all that's out;" in St. Joe, "the benzine has the upper hold;" in Omaha "he's on it bigger'n an Injun;" in Denver "he slung in a bowl too much;" in Cheyenne "the duffer's got it in the neck;" in Leadville "the galoot's on a roarer agin!;" in Bismark "he fills up with bug juice and gets fuller'n a goose"...
From the Athens Messenger, Athens, Ohio, 1886:
"Cannot you imagine, Mr Tower, that you hear the tremendous lion-like roar of the cataract even now?"
He shock his head. "No, Miss, no; I couldn't bring myself to imagine such a thing, unless I had ginned up better than I'm likely to do today."
"And his grin seemed to intimate that possibly the brilliant play of my own fancy was due to alcoholic stimulant."
Clearly with so many meanings of the word, any of which could be the source of 'gin up', the derivation isn't straightforward. The last two meanings of gin given above both have traceable links to 'gin up'. Apart from the use of the word gin, they appear to be unconnected.
So, we have two phrases:
- To 'gin up' - 'to excite or enliven', possibly related to 'ginger up'.
- To 'gin up' - 'to drink', particularly gin.