Worldly hold-up man eventually scratching back (5)
I believe the answer is:
atlas
'eventually scratching back' is the definition.
I can't judge whether this defines the answer.
'worldly hold-up man' is the wordplay.
'worldly' becomes 'ats' (I am not sure about this - if you are sure you should believe this answer much more).
'hold' indicates putting letters inside.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'man' becomes 'Al' (man's name).
'al' back-to-front is 'la'.
'ats' placed around 'la' is 'ATLAS'.
Can you help me to learn more?
(Other definitions for atlas that I've seen before include "In Greek myth, a Titan made to support the heavens" , "Sort of book" , "Titan compelled by Zeus to support the sky" , "Sky-toting Titan" , "Titan who held up the sky" .)