Xiru or chiru, is the pawn, a country man. It's also slang for friend or partner in Rio Grande do Sul.
Xirú is a term used in the pampa region of Rio Grande do Sul to call or refer to a man who is esteemed, also known as "old Indian", an expression that also designates a relationship of friendship and respect between men.
The word originated in the Tupi-Guarani language, spoken by the Indians of the South of South America before the arrival of the Portuguese and Spanish. Today it is a regionalist term from the state of Rio Grande do Sul, which arose from the vocabulary created with the miscegenation between the Guarani Indians, the Spaniards and the Portuguese who arrived here colonizing the South of South America.
A xirú is a man from the countryside, with a loyal posture, true and attached to his roots. The term was usually related to that of indigenous origin, which has the physical features of the Guaraní Indians. But in modern use you no longer find this difference due to physical characteristics.
There are records of the use of the word chirua as feminine in xirú. But the most common is the use of chinoca for the pawn's wife.
Chinoca also has an affectionate meaning, it is the companion gift of the farmer. Although there is also reference to the term chinoca as a diminutive of china. China she is the woman who accompanied the men traveling across the pampa, working as a prostitute.