For every lyric was unreasonable (8)
I believe the answer is:
perverse
'unreasonable' is the definition.
(I've seen this before)
'for every lyric' is the wordplay.
'for every' becomes 'per' ('per' means 'for each' or 'for every').
'lyric' becomes 'verse' (I can't explain this - if you can you should believe this answer much more).
'per'+'verse'='PERVERSE'
'was' acts as a link.
Can you help me to learn more?
(Other definitions for perverse that I've seen before include "Deliberately contrary" , "Deliberately departing from what is reasonable" , "Cross-grained" , "Obstinate" , "'Contrary to what's considered right, proper or good (8)'" .)