A humorous alteration of ‘au revoir’ after the noun ‘reservoir’, the exclamation ‘au reservoir’ is first recorded in Little Pedlington and the Pedlingtonians (London, 1839), by the English author John Poole (1786-1872).
First attested in 1943, the British-English colloquial phrase ‘to go (all) round the houses’ means ‘to get to the point in a lengthy or roundabout way’, from its literal sense, ‘to take an unnecessarily circuitous route to one’s destination’.
The phrase ‘all behind, like a cow’s tail’ and its variants mean ‘left behind’ and ‘late in accomplishing a task’. They appeared in print in the mid-19th century in the USA, Australia and Britain.
‘yahoo’: rude, noisy or violent person—word invented by Jonathan Swift (1667-1745) as the name of a race of brutish creatures resembling men in Gulliver’s Travels (1726)—came to be applied to the orang-utan
‘to take the Fifth’: to decline to reveal one’s own secrets—from ‘to take the Fifth Amendment’: to appeal to Article V of the original amendments to the U.S. Constitution, which states that “No person […] shall be compelled in any criminal case to be a witness against himself.”
‘Sydney or the bush’: all or nothing (1902)—based on the metaphorical opposition between an easy life in the city and a hard life working in the outback, this phrase was apparently originally used by people risking all on the toss of a coin.
British English: a drinking tour of a number of pubs or bars—but first appeared in 1909 with specific reference to an organised form of propaganda consisting in sending a person from pub to pub in order to promote the Conservative cause
denotes a situation in which the alternatives are considered equivalent—first recorded, as ‘six of the one and half a dozen of the other’, on 24th April 1790 in the journal of Ralph Clark, a British naval officer—synonym: ‘(as) broad as long’
‘to plough a lonely furrow’, or ‘one’s own furrow’ (UK, 1901): to carry on without help, support or companionship—French ‘creuser son sillon’ (‘to dig one’s own furrow’, first used by Voltaire): to carry out with courage and perseverance the task undertaken
‘dunce’: originally a follower of John Duns Scotus (circa 1265-1308), scholastic theologian; in the 16th century, Scotus’s system was attacked with ridicule by the humanists and the reformers as a farrago of needless entities and useless distinctions