To: ALL - My sincere apologies for putting the request first into the wrong section twice, i.e. English missing / German missing. I must have a penchant of clicking links to the wrong Forums... I just wanted to make a case for the word to be added to Leo - after a discussion, of course. So this section here finally seems the correct one for such purpose.
To: wienergriessler - Am I entirely wrong in thinking that the 'preferred' German translation of the English adjective seems to sit better as the 'preferred' adverb than any one of the collected adjectives I listed (btw. thank you to the contributors), since ehedem conveys the intended meaning and meets the fitting register, too? We have already the caveat in English that ci-devant is quite obviously appropriated from the French to replace the common 'formerly' when in the original French 'ci' is indeed an adverb which then combines with 'devant' - which originally was used as an adverb, too. - The combined remain invariable so, if I understood the entry in Le Petit Robert correctly. Ce-devant in the sense under discussion was an adverb at the time of the French Revolution whose meaning has since fallen out of fashion in modern French. Not so with the British. OED lists examples of its use in English from late 19C. However, the way Beatrice Webb uses the term in the 30s of the 19th C turns the hitherto implied emphasis of a formerly 'higher station' upside down (the now captain used to be a peasant) which carries more than a bit of irony while tempering the fun-fact that 'one does know some French'. To sum it up, I am saying that English made an adjective out of the French adverbial meld - So, please tell me, why should we be bogged down here by qualms of principle concerning word classes when translating the English into appropriate German by turning it back to an adverb fits the bill? The French no longer understand ci-devant in this context and the slight irony in its English usage may come through in the German as well as it may ever get - sadly the nagging over-the-top use of the vieux French with the tit-bit concealed snobbery cannot be fully replicated in German. But even a good 'second best' could serve as pragmatic translation - where so far there has been none at all.
To: eastworld - The list of German vocabulary was (a) taking into account, and acknowledging the recent contributions by all the people interested in discussing the matter. (b) Some of the translations suggested seemed to come closer to the meaning, and register of the use of the French term in English. I hoped a fruitful discussion would ensue about which ones to chose and which ones to dismiss. Anyone is invited to have a say - however, no one should feel required do do so.
To: no me bré - a small conjecture, if I may: like I mentioned in the original proposal under reference (3), ci-devant does have a full entry in the eminent OED, which I even abbreviated for the purpose required in my application for having the word included in Leo; while online access is restricted, I can assure you that it does exist therein. Also, as I referred to already in (2), prioritising this reference for the sole purpose of free access by all, Google offers an English definition of ci-devant giving the exact meaning tallying with what Webb writes in her Diary. Google says it uses a dictionary from the 'Oxford Languages' family of dictionaries, which offers a very short, but concise definition, obviously extracted from the full corpus. You also found additional sources.
In the OED ci-devant is rated 3 out of 5 in terms of rarity, so any claim this is a completely outlandish piece of vocabulary is mute.
I have explained in more detail (see in my response to wienergriessler above) why I see no serious issue with the English adjective use of the original (old) French adverb being translated into German as an adverb and hope Leo will consider these points and receive ci-devant (= formerly) [dated, humorously] = ehedem into its realm for the benefit of - some - users. A German source using the exact same translation has been given.
Thank you all for your help so far.