Absurd rail works receiving allocated quantity (10)
I believe the answer is:
irrational
'absurd' is the definition.
(I've seen this in another clue)
'rail works receiving allocated quantity' is the wordplay.
'works' is an anagram indicator (letters worked into a new form).
'receiving' is an insertion indicator.
'allocated quantity' becomes 'ration' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rail' is an anagram of 'iral'.
'iral' placed around 'ration' is 'IRRATIONAL'.
Can you help me to learn more?
(Other definitions for irrational that I've seen before include "nuts" , "Unreasonable" , "Illogical" , "not sensible" , "Crazy" .)