The Spanish word 'guaraní' comes from the indigenous Guaraní language, where it originally combined elements from two words: 'abá' meaning 'man' and 'guariní' meaning 'warrior' or 'to wage war'. This combination reflects how the term came to refer to both the Guaraní people and their language. The word essentially described the warrior people who spoke this language, before becoming the standard name for both the ethnic group and their language in Spanish.

While 'guaraní' is a unique term in Spanish specifically referring to this indigenous people and their language (as well as Paraguay's currency), there aren't any simpler or more common Spanish words that share its etymology, as it comes directly from the Guaraní language rather than from Latin or other common sources of Spanish vocabulary.

There aren't any common English words directly related to 'guaraní', as it comes from the indigenous Guaraní language of South America. The word has been borrowed into English unchanged, just as in Spanish, specifically to refer to the Guaraní people, their language, or the Paraguayan currency.