f17r

[MarcoP]

But ƺ stands not only for –um, -em, or, even –m. It can be –et, -it or –ed. For example, sƺ stands for sed, scƺ – for scit, and so on.What is more, ƺ was used as –um and –et in the same text, but in different words. Usually it could be understood  due to a sense of a text and construction of a sentence. Lucƺ is not an exclusion, it can mean You are not allowed to view links. Register or Login to view. as much as lucem or lucum. I’m not sure that the same shortened word can be used for two different forms of a real word in the same text. I think scribes usually chose an abbreviation for one of them. Probably, it depends on local traditions and own habits of scribes.
Logically, the horizontal bar in lucˉƺ may mean the dropped “n”, so it can be the verb lucent (3th person, present, plural).

Thank you, Searcher! Well researched and clearly presented! 
"lucent" now seems to me an excellent candidate, though interpreting the whole sentence remains an apparently impossible challenge.