"Just think ... " (7)
I believe the answer is:
imagine
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">just think</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for imagine that I've seen before include "Suspect" , "Picture in one's mind" , "Suppose; conceive" , "Classic Lennon song" , "Fancy - Lennon song" .)