From Tobias Smollett’s The Expedition of Humphry Clinker – in Jeremy’s letter of April 30.
In the mean time, I must entertain you with an incident, that seems to confirm the judgment of those two cynic philosophers [my uncle Matthew Bramble and his friend Mr Quin]. I took the liberty to differ in opinion from Mr Bramble, when he observed, that the mixture of people in the entertainments of this place [Bath] was destructive of all order and urbanity; that it rendered the plebeians insufferably arrogant and troublesome, and vulgarized the deportment and sentiments of those who moved in the upper spheres of life. He said such a preposterous coalition would bring us into contempt with all our neighbours; and was worse, in fact, than debasing the gold coin of the nation. I argued, on the contrary, that those plebeians who discovered such eagerness to imitate the dress and equipage of their superiors, would likewise, in time, adopt their maxims and their manners, be polished by their conversation, and refined by their example; but when I appealed to Mr Quin, and asked if he did not think that such an unreserved mixture would improve the whole mass? ‘Yes (said he) as a plate of marmalade would improve a pan of sirreverence.
The OED gives sirreverence as in origin a shortening of saving your reverence -> save reverence -> sareverence -> sirreverence. The ‘beg your pardon’ sense would initially have followed whatever was said that may have been found indecent but the phrase/word itself later – to avoid the indecency altogether – came in as substitute. Presumably becoming an indecency itself. The first appearance in the clear sense of ‘excrement’ is from 1592 in R. Greene’s Black Bookes Messenger (sig. D3):
His face,… and his necke, were all besmeared with the soft sirreverence, so as hee stunke.
Peter Motteux’s 1694 translation of Rabelais (bk4.52) includes another instance:
For four … Days I hardly scumber’d one poor Butt of Sir~reverence
Scumber itself is from Old French descombrer (modern decombrer) which means ‘to relieve of a load’. The evacuation sense adds itself.
Incidentally, Rabelais’ original text is:
ie ne fiantay qu’une petite crotte
Fienter has the meaning “Débarrasser (un cheval) de la fiente” (relieve [a horse] of shit) and crotte itself just means fiente.
Another reminder that Motteux is always the best Rabelais translator.