Choose one interesting word in the morning — 'enormous', 'reluctant', 'gleaming' — and say what it means together.
The game is to use it out loud during the day, in a real sentence that fits. Everyone in the house plays, adults included.
At dinner, count the uses. A wrong-but-reasonable use scores; the point is attempting the word, not deploying it perfectly.
A word is only learned once it has been produced in context, not merely recognised. Spreading attempts across a whole day gives spaced retrieval, which fixes vocabulary far more durably than repeating a definition.