In Spanish, the pronunciation is haag-waarr(purring)

EDIT
Source: The Collins English Dictionary © 2000 HarperCollins Publishers:

jaguar ['dʒægjʊə]
noun a large feline mammal, Panthera onca, of S North America, Central America, and N South America, similar to the leopard but with a shorter tail and larger spots on its coat
[ETYMOLOGY: 17th Century: from Portuguese, from Tupi jaguara, Guarani yaguara]