Croquet is a game played on a lawn, in which wooden balls are driven through a series of square-topped hoops by means of mallets.

The croquet term Aunt Emma designates:
– (the type of) an unenterprising or excessively defensive player;
– play regarded as characteristic of such a player.

Cf. also:
– ‘Aunt Edna’ (typical theatregoer of conservative taste)
– origin of ‘Aunt Sally’ (name of a British game)

Aunt Emma was originally the name of the fictitious author of a chapter on such tactics, in Croquet up to Date. Containing the Ideas and Teachings of the Leading Players and Champions. Edited by Arthur Lillie, Hon. Secretary for Croquet, All-England Lawn Tennis and Croquet Club, Wimbledon (London: Longmans, Green, and Co., 1900), by Arthur Lillie (1831-1911).

This fictitious author was mentioned in the review of Arthur Lillie’s book, published in The Glasgow Herald (Glasgow, Lanarkshire, Scotland) of Saturday 30^th June 1900:

It was about the middle of the ’sixties that croquet became popular in England. In 1869 the institution of a champion tournament gave it a recognised place amongst the outdoor games of the country. For about a dozen years it continued to number thousands of enthusiastic devotees; then suddenly all interest in it seemed to vanish. In 1882 the Wimbledon Club changed its name to the All-England Lawn Tennis Club, as no more croquet-players came forward to play. In 1895 croquet revived, and within two years again rose to the dignity and honour of a “championship” meeting. To what extent it has prospered and spread may be gathered from the fact that Mr Ayres sold 6000 specimens of one special mallet alone in the two years 1898-99. Those whose ideas of the game date back to the earlier period may feel inclined to sneer at the revival, more particularly if in the meanwhile they have fallen victims to golf. But, to say nothing of other changes and modifications, the adoption of 4-inch hoops, that is, of hoops only three-eights of an inch wider than the diameter of the ball, has made it a very difficult game—one that requires nerve, judgment, unremitting attention, and great physical nicety. […] The revival of croquet has, of course, been marked by the publication of various manuals setting forth its rules and imparting such information and instruction as seem likely to facilitate that straight shooting without which the young idea stands a very poor chance of figuring conspicuously in tournaments or competitions. Mr Arthur Lillie himself has already devoted a volume to the history, rules, and secrets of croquet. This second book of his may be looked upon as a sequel or a supplement to it. It deals very much more fully and thoroughly with separate points of the game and with various styles of play. What is perhaps of even greater importance, it does not set forth the views and opinions and theories of one expert only. Champions and leading players contribute their “ideas and teachings” to it. Thus, Mr C. D. Locock discusses what is, perhaps, of more importance than any other single point—the opening of the game; Mr Claude Heneage takes up the advanced game; what are called “cowardly tactics” are humorously, and yet very practically, treated by “Aunt Emma.”

The review of Arthur Lillie’s book, published in The Queen: The Lady’s Newspaper and Court Chronicle (London, England) of Saturday 21^st July 1900, gives these additional details:

One of the brightest chapters of a most readable volume must not go unmentioned. It is that in which “Aunt Emma” sets forth the merits and expounds the methods of the “cowardly game,” whereby mediocre players, with the aid of many bisques, may beat champions in handicaps, and win, together with a modicum of glory, “afternoon apostle” spoons, “just out” egg frames, and “brilliant lady’s” crescents and stars.

This illustration from Arthur Lillie’s Croquet up to Date was reprinted in The Queen (London, England) of 21^st July 1900:

In his column Mr. Dick, published in the Daily Herald (London, England) of Thursday 17^th May 1956, Alan Dick quoted the Roehampton croquet tournament manager as—apparently—using Aunt Emma metonymically:

I take off my hat, sprinkle this hoary head with ashes and make a deep bow of apology to the noble sport of croquet.
It isn’t the namby-pamby pat-a-ball of the vicar’s tea party I always thought it was. It’s a real wild game.
They are holding the first tournament of the season at Roehampton this week. And I went along there yesterday.
I came to scoff and stayed to play.
When I spoke of croquet in terms of hobble-skirts and side-whiskers, they nearly crowned me with a mallet—fair put me through the hoop.
No wonder. To play croquet you need the style of a golfer, the eye of a billiards player, the brain of a chess player—and the patience of Job.
Now I know where Davy Croquet got his name.
I met the tournament manager, a cherry-cheeked man with a name as French as croquet—Mr. V. A. de la Nougerede.
“Croquet is a great game,” he says, “full of tactics, technique and strategy. The game you are thinking of is as dead as the dodo.
“Those were the days when you could kick a football through the hoops, when you put your foot on your own ball and smacked Aunt Emma into the gooseberry bushes, where she found Uncle Isaac.
“Now there is the thickness of a penny between the hoop and the ball, and you have to have an athlete’s eye to run it through.”

Aunt Emma has been borrowed into American English. In Gentlemen’s Croquet: The Sport of Sports, by Dan Moffett, published in The Post (West Palm Beach, Florida) of Monday 14^th October 1985, Dan Moffett wrote of the development of croquet in the USA, and gave the following definition:

Aunt Emma — A conservative player who wastes time with uninspiring play. A wimp. A man named Alice.

The following is from Distance no problem for lovers of the game, by Nancy Graff, published in the Rutland Daily Herald (Rutland, Vermont) of Sunday 3^rd August 2014:

Beating Aunt Emma seems like poor sport, but in the refined game of six-wicket American croquet, it’s sometimes the best strategy. “Aunt Emma” is the nom de mallet of any croquet player whose plan for the game is simply to be a spoiler, someone who wreaks havoc with unpredictable shots so that opponents have a hard time advancing toward the stake. At these times, the only way to get rid of dear old Emma is to best her.

An extended use of Aunt Emma occurs in Delay tactic could pay off big for S.C., published in The Atlanta Journal-Constitution (Atlanta, Georgia) of Sunday 16^th September 2012:

Ever hear of an Aunt Emma?
It’s a croquet term, usually given to someone who, instead of trying to score or succeed on their own terms, simply tries to block or impede the success of their opponent.
Probably some folks in Georgia think the Savannah River Maritime Commission is a bit of an Aunt Emma (and that’s putting it politely).