Rev fills a box with church literature lacking in content (10)
I believe the answer is:
accelerate
'rev' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for accelerate that I've seen before include "Quicken" , "snowball" , "Go faster" , "Crank up" , "Increase speed" .)