An element from Ulster found in Czech Republic retiring (4)
I believe the answer is:
zinc
'an element' is the definition.
(zinc is a kind of element)
'ulster found in czech republic retiring' is the wordplay.
'ulster' becomes 'NI' (Northern Ireland).
'found in' indicates putting letters inside.
'czech republic' becomes 'cz' (I've seen this in other clues).
'retiring' says the letters should be written backwards.
'ni' inserted into 'cz' is 'cniz'.
'cniz' in reverse letter order is 'ZINC'.
'from' is the link.
(Other definitions for zinc that I've seen before include "Metallic element used in batteries" , "coat for protection" , "White metallic element used in alloys" , "it might be galvanising" , "Sivery-white metal" .)