diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index e3a0258d54..8b9dbc68e6 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -770,6 +770,7 @@ class WordsModel(QAbstractTableModel):
             self.beginRemoveRows(QModelIndex(), row, row)
             del self.items[row]
             self.endRemoveRows()
+        self.words.pop(w, None)
         return new_key
 
     def update_word(self, w):