a.word-link {
  padding-right: 10px;
  cursor: default;
  text-decoration: none;
  color: black;
}
a.word-link:hover {
  background-color: #d7f1f8;
}
a.word-link:hover:after {
  background:rgba(1.9,1.2,10.3,30.7);
  color:#fff;
  content:attr(rel);
  display:block;
  margin-top:-42px;
  position:absolute;
  white-space:nowrap;
}

span.word-link {
    border-bottom: 1px dotted #000;
    color: black;
}
span.word-link:hover {
  background-color: yellow;
}