(n.) underhand or dishonest behaviour
It’s tempting to think that as another word for disreputable, devious behaviour—and with its subtle nod towards the word “skull”—skulduggery might have some kind of connection to the swashbuckling exploits of pirates and buccaneers. In fact, there’s no such connection at all; in fact, it’s all a lot more bizarre than that.
Skulduggery first appeared in the language, with its modern sense and spelling, in the mid 1800s—its earliest record taken from an American newspaper of 1867 that described it as a “mysterious term ... used to signify political or other trickery”. Before then, skullduggery was sculduddery, an old Scots dialect word that nineteenth-century lexicographer John Jamieson defined as:
A term, now used in a ludicrous manner, to denote those causes that come under the judgement of an ecclesiastical court, which respect some breach of chastity.
John Jamieson, An Etymological Dictionary of the Scottish Language (1808)
So skullduggery—or rather sculduddery—seemingly began life as a legal term referring to any crime or misdemeanour that comprised a “breach of chastity” in the eyes of Scotland’s strict Presbyterian courts. In that sense, the term has been unearthed as far back as 1663 in a letter written by the Earl of Argyll to Sir Archibald Primrose, the Clerk-Register of the Scottish court, in which he mentions that an unnamed acquaintance has been arrested “not for sculdudry ... but for a less gentlemanny crime: theft”.
Theft carried the threat of the death penalty at that time, and the Earl was writing to the clerk-register to request leniency in passing sentence. The “more gentlemanny” crime of sculduddery meanwhile carried a less severe (if more humiliating) penalty, as explained in another letter dated 1730:
If any one be brought before a presbytery to be questioned for sculduddery, i.e. fornication or adultery ... the offender ... will be avoided by his friends, acquaintance, and all that know him ... I was told in Edinburgh of a certain Scots colonel, being convicted of adultery ... was sentenced to stand in a hair cloth at the kirk door every Sunday morning for a whole year, and to this he submitted. At the beginning of his penance he concealed his face as much as he could, but three or four young lasses passing by him, one of them stooped down, and cried out to her companions, “Lord! it’s Colonel——.” Upon which he suddenly threw aside his disguise, and said, “Miss, you are right; and if you will be the subject of it, I will wear this coat another twelvemonth.”
Edward Burt, Letters from a Gentleman in the North of Scotland (1754)
Whether this anecdote is true or not, it shows that the legal definition of sculduddery was still in place by the mid 1700s, but the fact that John Jamieson—compiling his dictionary just after the turn of the nineteenth century—pointed out that sculduddery is “now used in a ludicrous manner” suggests that this meaning had already weakened by the early 1800s. Indeed, by the 1820s sculduddery had become little more than a byword for obscenity or vulgarity, and it’s from there that the modern sense of “disreputable behaviour” or “dishonesty” —and eventually the modern spelling skullduggery—emerged in the mid nineteenth century.