O'er and o'er (3)
I believe the answer is:
oft
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">o'er and o'er</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 oft that I've seen before include "Frequently, as the poet would have it" , "time and again in literature" , "Frequently in archaic term" , "Old song'... in the stilly night'" , "Frequently, in verse" .)