Was acquainted with (4)
I believe the answer is:
knew
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">was acquainted with</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 knew that I've seen before include "Had learnt; sounds like modern" , "Was aware of the fact" , "Understood" , "Was cognisant or aware of" , "Was conscious of" .)