Double or Nothing
In a “Double or Nothing,” each square in the grid gets either two letters or no letters at all. At least half the squares in every row or column will have letters in them.
ACROSS
1 Strong and vigorous
2 Central part
3 Fit together neatly, as the teeth of gearwheels
4 Dutch cheese
5 Place where you might buy cheese, Dutch or otherwise
6 Recite in a singsong manner
DOWN
1 Arrived on a horse (2 words)
2 Wake up again after being unconscious (2 words)
3 Tired out
4 Make more aerodynamic
Update: Here’s a printable version.