Speak pompously, hold forth (5)
I believe the answer is:
orate
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">speak pompously</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(to orate is to give a speech)</span><br/ ><br/ >'<span class="explanation-format__original">hold forth</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for orate that I've seen before include "Give a formal address" , "Speak publicly" , "Pontificate" , "Give speech" , "Make a formal speech" .)