Little dog, briefly (3)
I believe the answer is:
pom
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">little dog briefly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(Pom is short for Pomeranian; 'briefly' asks for an abbreviation)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pom that I've seen before include "Small dog (colloq.)" , "Shortened name for a breed of dog" , "Australian slang for British migrant" , "Limey in Oz" , "Little dog" .)