He has the weight of the world on his shoulders (5)
I believe the answer is:
atlas
'he has the weight of the world on his shoulders' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for atlas that I've seen before include "I carry a huge weight" , "Sky carrier - map book" , "Album of maps" , "Titan who held up the sky" , "Large-format book" .)