Private Sub RichTextBox1_Click()
Dim pos1 As Integer
Dim pos2 As Integer
Dim txt As String
Dim txtlen As Integer

    ' Find the beginning of the word.
    pos1 = RichTextBox1.SelStart
    txt = RichTextBox1.Text
    If pos1 > 1 Then
        Do While Mid$(txt, pos1, 1) <> " "
            pos1 = pos1 - 1
            If pos1 <= 1 Then Exit Do
        Loop
        If pos1 > 1 Then pos1 = pos1 + 1
    End If
    
    ' Find the end of the word.
    pos2 = pos1
    txtlen = Len(txt)
    Do While Mid$(txt, pos2, 1) <> " "
        pos2 = pos2 + 1
        If pos2 > txtlen Then Exit Do
    Loop
    If pos2 <= txtlen Then pos2 = pos2 - 1
    
    txt = Mid$(txt, pos1, pos2 - pos1 + 1)
    MsgBox txt
End Sub