Sub Highlight_ER_in_SEVERE()
'
'Search for "severe". Highlight only the letters "er".
Set oRng = ActiveDocument.Range
With oRng.Find
  .MatchWholeWord = True
  .Text = "severe"
  .Wrap = wdFindStop 'stops at the end of the document
  While .Execute
    oRng.HighlightColorIndex = wdGreen
  Wend
End With
End Sub

Sub Highlight_ER_in_SEVERE()
'Search for "severe". Highlight only the letters "er".
Dim oRng As Range
With ActiveDocument.Range
  With .Find
    .MatchWholeWord = True
    .Text = "severe"
    .Wrap = wdFindStop 'stops at the end of the document
  End With
  While .Find.Execute
    Set oRng = .Duplicate
    With oRng
      .Start = .Start + 3
      .End = .End - 1
      .HighlightColorIndex = wdGreen
    End With
    .Collapse wdCollapseEnd
  Wend
End With
End Sub

Sub Sev_ER()
Dim r As Range
Set r = ActiveDocument.Range
With r.Find
   Do While .Execute(findtext:="severe", Forward:=True) = True
      With r
         .MoveStart 1, 3
         .MoveEnd 1, -1
         .HighlightColorIndex = wdGreen
         .Collapse 0
      End With
   Loop
End With
End Sub