Infantas is a Spanish term used to refer to the daughters of a monarch. The term is somewhat specific, and there aren't many direct synonyms for it in English. However, there are a few phrases that can be used to convey the same meaning. For example, "princesses" is the most common term used to describe daughters of a monarch in English. "Royalty," "nobility" and "royal lineage" are other phrases that can be used to indicate similar meaning. While "infantas" has a distinct connotation of Spanish royalty, these synonyms can be used more broadly to describe any daughter(s) of royalty.