Delay said to be a burden (4)
I believe the answer is:
wait
'delay' is the definition.
(I know that delay can be written as wait)
'said to be a burden' is the wordplay.
'said to be' shows a homophone (sound like).
'a burden' becomes 'weight' (I've seen this before).
'weight' sounds like 'WAIT'.
(Other definitions for wait that I've seen before include "Be patient" , "Stay" , "Serve on tables" , "Watchman" , "Period of delay" .)