Codenames scales from 4 to 16 players without changing the rules. Spymasters give one-word clues that link multiple words on a grid; field operatives guess. Score by uncovering your team's words first, lose by uncovering the assassin.
Both roles are rewarding. Spymastering rewards clever wordplay; guessing rewards reading your spymaster. The "I knew you'd think of that" moments are the heart of the game.
The Pictures variant is excellent for non-native English speakers. The Duet 2-player co-op is excellent for couples. The original word version remains the right buy for groups.