Letter flourish (5)
I believe the answer is:
serif
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">letter flourish</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for serif that I've seen before include "One feature of text" , "Letter feature" , "Little bit of character" , "additional line in letter?" , "addition to character?" .)