The Wikipedia article of the day for July 18, 2021 is Temporary gentlemen.
“Temporary gentlemen” is a colloquial term referring to male officers of the British Army who held temporary (or war-duration) commissions, particularly when such men came from outside the traditional officer class. Historically the officers of the British Army were drawn from the gentry and upper middle classes. The First World War required a rapid expansion of the officer corps and more than 200,000 additional officers were recruited, many on temporary commissions. Many of these were drawn from the lower middle and working classes. They came to be referred to as “temporary gentlemen” with the expectation that they would revert to their former social standing after the war. The term was revived in the Second World War, which saw a similar increase in the number of officers holding temporary commissions. The term continued to see use for officers commissioned from those conscripted for National Service, which lasted until 1963.