The classic memory pairs game with a twist: the matching cards aren't identical, they're synonyms. Flip two cards; if they mean the same thing (like brave and courageous), they stay. Find every pair in as few moves as you can: harder difficulties mean bigger boards.
Synonym knowledge is tested directly in 11+ verbal reasoning and indirectly everywhere else. Pairing brave with courageous under memory-game conditions forges a much stronger link than reading a word list ever does. The recap at the end shows all eight pairs: worth reading aloud together.