Crop broadcast for web (4)
I believe the answer is:
maze
'for web' is the definition.
(thesaurus)
'crop broadcast' is the wordplay.
'crop' becomes 'maize' (I've seen this before).
'broadcast' indicates a 'sounds like' (homophone) clue (how the word might sound on the radio or TV).
'maize' sounds like 'MAZE'.
(Other definitions for maze that I've seen before include "confusion" , "Complex set of paths" , "Labyrinth, tangle" , "Complex network" , "Route-finding puzzle" .)