Driven crazy by closing time! (4)
I believe the answer is:
made
'driven crazy by closing time' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Maybe there's an association between them I don't understand?
'driven crazy by' is the wordplay.
'driven' becomes 'e' (I am not sure about this - if you are sure you should believe this answer much more).
'crazy' becomes 'mad' (synonyms).
'by' means one lot of letters go next to another.
'e' after 'mad' is 'MADE'.
Can you help me to learn more?
(Other definitions for made that I've seen before include "Manufactured" , "Built" , "Performed" , "Produced" , "Constructed" .)