Indication; authorise (4)
I believe the answer is:
sign
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">indication</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that indication can be written as sign)</span><br/ ><br/ >'<span class="explanation-format__original">authorise</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that sign is a type of formalize)</span><br/ ><br/ ></span>
(Other definitions for sign that I've seen before include "Authorise with a name" , "Communicate to the deaf" , "Traffic control - to write one's name" , "Omen or indication" , "Leo, for instance" .)