Scientist from site oddly held by a German repeatedly (8)
I believe the answer is:
einstein
'scientist' is the definition.
(Einstein is an example)
'site oddly held by a german repeatedly' is the wordplay.
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
'held by' means one lot of letters goes inside another.
'a german' becomes 'ein' ('a' in German).
'repeatedly' shows that letters should be duplicated.
The alternating letters of 'site' are 'st'.
'ein' doubled is 'einein'.
'st' going within 'einein' is 'EINSTEIN'.
'from' is the link.
(Other definitions for einstein that I've seen before include "Albert -, famous scientist" , "Set nine up for his theory of relativity" , "Brilliant scientist" , "E=mc2 physicist" , "Albert, who founded the theory of relativity" .)