"Jaboncillo" is the Spanish term for a kind of tree that produces oily nuts, but it is also used to refer to other things, such as a mild soap or a small, round candy. Some synonyms for "jaboncillo" might include "soapwort", "saponin", or "soap nut". These terms all relate to the saponins found in the plant, which can be used as a natural soap or detergent. Other similar words might include "soapberry", "washing nut", or "reetha", as these are also types of plants with similar properties. Overall, "jaboncillo" is a versatile term that can refer to a wide range of natural cleaning agents and plant products.