amancebarse

A somewhat old-fashioned or legal/formal verb meaning to live together as an unmarried couple — historically used with moral or legal disapproval (concubinage), it now reads as dated or judgmental; convivir or vivir juntos are the neutral modern equivalents.

• En el siglo XIX, amancebarse sin estar casados era mal visto. — In the 19th century, living together unmarried was frowned upon.
• El cura del pueblo se amancebó, según cuentan los archivos parroquiales. — The village priest lived with a partner out of wedlock, according to the parish records.
• La ley antigua castigaba a quienes se amancebaban abiertamente. — The old law punished those who openly lived together unmarried.

Using amancebarse as a neutral, modern way to say 'to move in together' — it carries an old-fashioned moralizing tone; convivir or irse a vivir juntos is what a contemporary speaker would actually say.

Often confused with convivir.