Chap concealing nothing that's burdensome (4)
I believe the answer is:
load
'that's burdensome' is the definition.
I can't judge whether this defines the answer.
'chap concealing nothing' is the wordplay.
'chap' becomes 'lad'.
'concealing' means one lot of letters goes inside another.
'nothing' becomes 'o' (looks like zero - 0).
'lad' going around 'o' is 'LOAD'.
Can you help me to learn more?
(Other definitions for load that I've seen before include "Weight to be transported" , "Weigh down" , "Weight, source of pressure" , "Amount" , "pack" .)