The Greatest Gymnast of All by Stuart J. Murphy is a perfect book on opposites for early elementary children. If you’ve got the physical space, I’d recommend reading it aloud together, then reading it again and invite your child to do the actions in the way the story describes.
One really nice feature of this picture book is that it presents additional ideas for discussing opposites with your child at the end of the book. One creative idea you can adapt is to make a charades game out of acting out sets of opposites. You could work from a word bank you make yourself, or for a challenge, just use your imagination.