Spanish is full of ambiguous words. Just looking around at my desk, I can find...
papel - paper/role
monitor - monitor/supervisor (in Arg, also the student in charge of class materials)
factura - invoice/a kind of pastry (Arg)
caja - box/till/case/drum/soundbox
revista - magazine/review
And let's not start with the verbs...
sonreír - smirk/grin/smile
arrancar - pull out / pull up / pluck / tear out / rip out / blow off / snatch / wrench / start / start a vehicle or machine / boot / set sail...