Vet, verify (5)
I believe the answer is:
check
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">vet</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(vet can mean to test or check)</span><br/ ><br/ >'<span class="explanation-format__original">verify</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(checking is a kind of verifying)</span><br/ ><br/ ></span>
(Other definitions for check that I've seen before include "Examination" , "Verify, examine" , "Restrain; vet" , "threat to king" , "Restrain; square pattern" .)