‘double Dutch’, 19th century—from ‘Dutch’ in the sense of a language that few people can speak, and ‘double’ as a mere intensifier—‘High Dutch’, 17th century—loan translation from French ‘haut allemand’ (= ‘High German’), used in the sense of gibberish
USA—‘to go Dutch’ (1907): to have every participant pay their own expenses, or share expenses equally—via ‘to go Dutch treat’ (1887), from ‘Dutch treat’ (1873): a meal, etc., at which each participant pays their share of the expenses—from a German practice
During the Cold War, especially in the context of a possible nuclear war, ‘better red than dead’ was used to warn against uncompromising opposition to communism, while ‘better dead than red’ was used to express unconditional opposition to communism.
A calque of German ‘blauer Montag’, ‘blue Monday’ originally denoted a Monday on which people chose not to work as a result of excessive indulgence over the course of the weekend. Under the influence of the adjective ‘blue’ in the sense ‘dismal’, it came to denote a Monday that is depressing or trying.
The 1776 French translation of Laurence Sterne’s ‘The Life and Opinions of Tristram Shandy’ gave to French ‘dada’, a child’s noun for ‘horse’, the figurative meaning of ‘favourite pastime’ or ‘pet idea’.
‘Hobby’, diminutive of ‘Hob’, pet form of ‘Robert’, was used to denote a small horse, hence a child’s toy with a horse’s head, hence a favourite occupation—cf. French ‘dada’, child’s word for horse, used to denote a favourite pastime
An expression of indifference to, or resigned acceptance of, a state of affairs, ‘san fairy ann’ jocularly represents the French phrase ‘ça ne fait rien’, meaning ‘that doesn’t matter’. It originated in army use on the Western Front during the First World War.
18th century—origin unknown—perhaps originally imitative and comparable to, or derived from, ‘tantara’, denoting the sound of a trumpet, hence an uproar—or from obsolete French ‘trantran’, synonym of ‘tantara’
in full ‘Quasimodo Sunday’: the Sunday after Easter—from the opening words of the Latin introit for that day, ‘quasimodo geniti infantes’, ‘as newborn babies’