an expert
Ask an expert.
El juez ha pedido a un experto que lo aclare.
The judge has asked an expert to clarify it.
— Anatomía de una Caída (2023)
Mi marido es un experto, cuando se trata de la preparación de comida china.
My husband is an expert when it comes to preparing Chinese food.
Para alguien que se supone que es un experto, usted no parece saber mucho.
For someone who is supposed to be an expert, you don’t seem to know much.
He is an expert.