Pedant, fusspot (8)
I believe the answer is:
stickler
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">pedant</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(a pedant is a stickler for detail)</span><br/ ><br/ >'<span class="explanation-format__original">fusspot</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for stickler that I've seen before include "One who insists on something, like punctuality" , "Pernickety person" , "Nit-picker" , "Trickles for someone who insists" , "Someone fastidious" .)