To limit share in dilapidated lair is absurd (10)
I believe the answer is:
irrational
'absurd' is the definition.
(I've seen this in another clue)
'to limit share in dilapidated lair' is the wordplay.
I cannot quite see how this works, but
'limit' could be 'ration' (rationing is a kind of limiting) and 'ration' is present in the answer.
an anagram of 'lair' is 'iral' which is located in the left over letters.
This accounts for all the letters.
This explanation may well be incorrect...
'is' is the link.
Can you help me to learn more?
(Other definitions for irrational that I've seen before include "making no sense" , "Kind of numbers" , "Unreasonable" , "Not logical" , "Illogical" .)