Definition of "soporific"
soporific
noun
plural soporifics
adjective
comparative more soporific, superlative most soporific
(pharmacology) Tending to induce sleep.
Quotations
For we are not here to understand, as perhaps some have, that an author actually falls asleep while he is writing. It is true, that readers are too apt to be so overtaken; […] To say the truth, these soporific parts are so many scenes of serious artfully interwoven, in order to contrast and set off the rest;
1749, Henry Fielding, chapter I, in The History of Tom Jones, a Foundling, volumes (please specify |volume=I to VI), London: A[ndrew] Millar, […], book V
I should imagine that the smooth riding and the quietness of the diesel or electric cab, coupled with the effect on the eyes of endless successions of sleepers disappearing from sight immediately under the driver's eyes, might in time have a soporific effect, so that the company of a second man, who can assist in signal observations when he is not at work in the engine cab, seems highly desirable in such conditions.
1961 July, Cecil J. Allen, “Locomotive Running Past and Present”, in Trains Illustrated, page 401
Quotations
COP stands for conference of the parties under the UNFCCC, and the annual meetings have swung between fractious and soporific, interspersed with moments of high drama and the occasional triumph (the Paris agreement in 2015) and disaster (Copenhagen in 2009).
2019 December 2, Fiona Harvey, “Climate crisis: what is COP and can it save the world?”, in The Guardian