Sub BulkFindReplace()
Application.ScreenUpdating = False
Dim FList As String, RList As String, j As Long
FList = "School,Library,Technical,Mathematics,Physics,Chemistry,students,student,teachers,teacher"
RList = "Sch,lib,Tech,Maths,Phys,Chem,stdnts,stdnt,tchrs,tchr"
With ActiveDocument.Range.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .Format = False
  .Forward = True
  .MatchCase = False
  .MatchWholeWord = True
   'Process each word from the Find/Replace Lists
  For j = 0 To UBound(Split(FList, ","))
    .Text = Split(FList, ",")(j)
    .Replacement.Text = Split(RList, ",")(j)
    .Execute Replace:=wdReplaceAll
  Next
End With
Application.ScreenUpdating = True
End Sub