Try:
Sub BulkHighlighter()
Application.ScreenUpdating = False
Dim j As Long, StrFnd As String, HiLt As Long
HiLt = Options.DefaultHighlightColorIndex
Options.DefaultHighlightColorIndex = wdBrightGreen
StrFnd = InputBox("Insert your 'Find' terms with | delimiters, for example:" & vbCr & "the|quick|brown|fox")
With ActiveDocument.Range.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .MatchWholeWord = True
  .MatchCase = False
  .Replacement.Highlight = True
  For j = 0 To UBound(Split(StrFnd, "|"))
    .Text = Split(StrFnd, "|")(j)
    .Replacement.Text = "^&"
    .Execute Replace:=wdReplaceAll
  Next
End With
Options.DefaultHighlightColorIndex = HiLt
Application.ScreenUpdating = True
End Sub