Ajeno

Ajeno is a Spanish adjective used to describe something that belongs to another person or is outside one’s own domain, experience, or concern. It can mean foreign, external, or not related to the speaker. Common uses include expressions such as algo ajeno a mis planes (something not related to my plans) or no es ajeno a su influencia (it is not immune to or unaffected by his influence). The word often contrasts with propio, which means “one’s own.”

Etymology and usage notes: Ajeno derives from Latin alienus, meaning “belonging to someone else.” Over time it entered Spanish with the sense of distance or foreignness. The adjective agrees in gender and number: ajeno (masculine singular), ajena (feminine singular), ajenos (masculine plural), ajenas (feminine plural). It frequently appears with the preposition a, as in ajeno a, to indicate detachment or irrelevance: algo ajeno a X.

As a noun phrase, lo ajeno can refer to things that belong to others or to the realm outside one’s own concerns, as in defenderse de lo ajeno or preocuparse por lo ajeno. Its usage ranges from everyday speech to formal writing, and it often conveys a sense of distance, unfamiliarity, or estrangement.

Synonyms and related terms include extranjero, ajénese (less common), foráneo, and ajeno to express various shades of “not belonging to me” or “not part of this.” The opposite concept is propio, meaning “one’s own” or “belonging to oneself.”