Indigent, being reduced in rank? (3)
I believe the answer is:
Here is my best explanation:
'rank?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'indigent being reduced in' is the subsidiary indication.
'indigent being' becomes 'ge' (I can't explain this - if you can you should give a lot more credence to this answer).
'reduced' means to remove the first letter.
'in' with its initial letter removed is 'n'.
(Other definitions for gen that I've seen before include "opening book, in short", "The low-down", "'Information, colloquially (3)'", "Information (informal)", "Information (colloq.)", "Lowdown (sl.)", "Info", "Information yielded", "Knowledge" and "Informal information".)