Dumbfound (11)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dumbfound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for flabbergast that I've seen before include "Strike dumb" , "Astonish" , "floor" , "Astound" , "stunning" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dumbfound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stun that I've seen before include "Knock unconscious" , "deliver a knock-out blow" , "Concuss; amaze" , "Stagger, amaze" , "Amaze; knock senseless" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dumbfound</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that dumbfound can be written as nonplus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for nonplus that I've seen before include "Flummox" , "Baffle" , "'Disconcert, puzzle (7)'" , "Perplex completely with negative and positive" , "Perplex, confound" .)