

I’ve never heard “gyped” or “jipped”. I’d say you were “duped”.
But that could be because I speak a dialect which features strong yod-coalescence. So “dune” and “june” are pronounced the same. So perhaps I have heard it, but simply eggcorned it into “dupe”.
I thought for sure you’d be right. But it turns out, no! Dupe comes from 15th century French duppe, thieves’ jargon, thought to come from Latin huppe/hoopoe, an extravagantly crested bird. Duplicity comes from Latin duplicitatem “doubleness”.