The most ludicrous one left is lying in the way (8)
I believe the answer is:
silliest
'the most ludicrous one left is lying in the way' is the definition.
I can't tell whether this defines the answer.
'ludicrous one left is lying in the way' is the wordplay.
'ludicrous' indicates an anagram.
'one left' becomes 'L' (common abbreviation).
'lying in' becomes 'lie' (I can't justify this - if you can you should believe this answer much more).
'the way' becomes 'st'.
'l'+'is'='lis'
'lis' is an anagram of 'sil'.
'sil'+'lie'+'st'='SILLIEST'
Can you help me to learn more?
(Other definitions for silliest that I've seen before include "Most foolish" , "Being least sensible" , "Most stupid" , "Most unwise" , "Most ridiculous" .)