consustanciarse

A rare, theological and philosophical verb meaning to identify with something so completely that one becomes, in effect, one with it — related to consustancial, the term used in Christian doctrine for the Trinity being "of one substance." Outside theology and philosophy, identificarse con covers the everyday idea.

• El actor se consustanció de tal manera con su personaje que costaba distinguirlo. — The actor identified so completely with his character that it was hard to tell them apart.
• Los teólogos discuten cómo el Hijo se consustancia con el Padre. — Theologians discuss how the Son is consubstantial with the Father.
• Con los años, se consustanció con la misión de la organización. — Over the years, he became fully identified with the organization's mission.

Far too formal/theological for everyday speech — identificarse con or fundirse con is what a learner needs for the ordinary idea of "identifying closely with" something.

Often confused with identificar.