Uranium for example opposed by Einstein potentially (5)
I believe the answer is:
metal
'uranium' is the definition.
(thesaurus)
'opposed by einstein potentially' is the wordplay.
'opposed' becomes 'met' (I've seen this in another clue).
'by' is a charade indicator (letters next to each other).
'einstein potentially' becomes 'Al' (Albert Einstein).
'met'+'al'='METAL'
'for example' acts as a link.
(Other definitions for metal that I've seen before include "Maybe lead" , "Tungsten, for example" , "Like steel cutlery" , "Copper possibly" , "Eg, copper" .)