Fifty follows forty-nine? Well, no (3)
I believe the answer is:
ill
'well no' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'fifty follows forty-nine?' is the wordplay.
'fifty' becomes 'l' (Roman numeral).
'follows' means one lot of letters go next to another.
'forty nine?' becomes 'il' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'l' put after 'il' is 'ILL'.
Can you help me to learn more?
(Other definitions for ill that I've seen before include "Off colour?" , "Seasick" , "Green round the gills" , "Groggy" , "Off-colour" .)