Adam's third son shifted most of these (4)
I believe the answer is:
seth
'adam's third son' is the definition.
(I've seen this before)
'shifted most of these' is the wordplay.
'shifted' is an anagram indicator.
'most of' means to remove the last letter.
'these' with its last letter taken off is 'thes'.
'thes' is an anagram of 'SETH'.
(Other definitions for seth that I've seen before include "Third son of Adam and Eve" , "Adam and Eve's third son" , "Younger brother to Cain and Abel" , "Indian novelist, Vikram" , "Old Testament character" .)