Brain teaser puzzles for adults come in a few broad styles. There are mechanical puzzles, such as interlocking metal or wooden pieces you have to take apart and put back together, logic puzzles that ask you to work out a single correct arrangement, and spatial puzzles where you fit shapes into a fixed space. Knowing which type someone enjoys makes it much easier to choose one they will actually sit down with.
To compare word games by pace and age suitability, and see which reward speed versus vocabulary, take a look Shop At Happy Puzzle the word games at outdoor garden games.
For a hand-picked selection of brain teasers across easy, medium and fiendish levels, have a look at the adult puzzle range at brain teaser puzzles.
To compare escape room games by difficulty and player count, and find one that suits your group, see the escape room range at games for children.
These games are a good pick if you want screen-free play that travels well and does not need a long rulebook. You can compare the full Genius line-up and read how each version plays at brain teaser puzzles.
Slower, more thoughtful word games suit older children and adults who like to plan a high-scoring play. These reward a wider vocabulary and a bit of tactics, so they are better kept for players who enjoy taking their time. If you are buying for a mixed-age family, a fast game is usually the safer bet, since it keeps the youngest involved rather than left behind.