This is the same thing as saying “Break a leg” to someone about to step on stage. The expression reflects a theatrical superstition in which wishing a person “good luck” is considered bad luck. Estonians are of completely the same eba/usklik (superstitious) mind. They have, in similar reverse fashion, the tradition of calling a crow valge lind (“white bird”), so it won't bring along the darkness of bad luck. The hunt (wolf), recently chosen to be Estonia's national animal, also has a multitude of aliases including võsa/villem (William of the forest), kriim/silm (stripy / streaky eye), Püha Jüri kutsikas (St. George's puppy), metsa/töll (someone who saunters (töllerdab) in the forest), and the S-E Estonian susi, so as to not invite bad luck by using its actual name.
Going fishing or on a hike? An Estonian will wish you “Kivi kotti!” (a stone in your bag), or “Nael kummi!” (a nail in your tire). At a recent performance, dancers were wished pind jalga – a splinter in their foot. And so, the wish on the school wall reads: “May you fail your exams miserably!” But means: You will all do really well!
Riina Kindlam, Tallinn