As far as possible, half of plinth has level support (3,6)
I believe the answer is:
nth degree
'as far as possible' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'half of plinth has level support' is the wordplay.
'half of' means to take half the letters.
'has' says to put letters next to each other.
'level support' becomes 'degree' (I can't justify this - if you can you should believe this answer much more).
'plinth' with half the letters taken is 'nth'.
'nth'+'degree'='NTH DEGREE'
Can you help me to learn more?
(Another definition for nth degree that I've seen is " An extreme extent".)