Declines travel east, then block books (4,2,3)
I believe the answer is:
goes to pot
'declines' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'travel east then block books' is the wordplay.
'travel' becomes 'go' (synonyms).
'east' becomes 'e' (abbreviation).
'then' says to put letters next to each other.
'block' becomes 'stop' (synonyms).
'books' becomes 'OT' (Old Testament).
'go'+'e'+'stop'+'ot'='GOES TO POT'
Can you help me to learn more?
(Other definitions for goes to pot that I've seen before include "Becomes bad" , "loses form" , "cracks up" , "Prepares to follow snooker player" , "Becomes ruined" .)