Gain knowledge (5)
I believe the answer is:
learn
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gain knowledge</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for learn that I've seen before include "Gain knowledge or skill" , "Absorb as knowledge, from book or experience" , "Come to know" , "teach illiterate" , "Take in" .)