Saliva dripping from the mouth, or a ship/person engaged in the slave trade.
The saliva meaning comes from Middle English slaveren, possibly from Old Norse slafrr (slime). The slave trade meaning comes from 'slave' + -er (one who does), referring to ships that transported enslaved people. The word has two very different origins that accidentally converged in spelling.
The word 'slaver' shows how shipping history literally corrupted language—the same term for a drooling animal mouth became synonymous with the horrific industrial machinery of human enslavement.
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