Think too highly of (8)
I believe the answer is:
overrate
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">think too highly of</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 overrate that I've seen before include "Make too much of" , "Think too much of" , "Rank too highly" , "Exaggerate" , "Score excessively" .)