Loot? Ltoo? Loto? Tolo? Tloo? Otol? Oolt? Olot? Olto? Ootl?
From Paper Cuts: “Its reference title is ‘Tool,’ presumably an anagram, somehow based on a character named Laura. But it is idle to speculate about the title or the meaning, his editor says, because Mr. Nabokov likes to play games with words, ideas and publishers, and it is impossible to tell until those shuffled cards are typed into a manuscript.”