Arrestar vs. detener
In Spanish, the words arrestar and detener both can mean to arrest, but they have slight nuances in usage and context.
Arrestar
B2Arrestar is used specifically to refer to the formal act of arresting someone, typically carried out by law enforcement officers.
La policía arrestó al ladrón después de una persecución.
(The police arrested the thief after a chase.)
Fue arrestado por conducir bajo la influencia del alcohol.
(He was arrested for driving under the influence of alcohol.)
Las autoridades arrestaron a varios sospechosos en la redada.
(Authorities arrested several suspects in the raid.)
Detener
B1Detener is a broader term that means to stop or to detain. When referring to an arrest, it implies taking someone into custody but may also mean stopping their actions or movement.
La policía detuvo al manifestante por desobedecer las órdenes.
(The police detained the protester for disobeying orders.)
Detuvieron al sospechoso en el aeropuerto.
(They detained the suspect at the airport.)
El guardaespaldas logró detener al agresor antes de que atacara al VIP.
(The bodyguard managed to stop the assailant before he attacked the VIP.)
Summary
While both arrestar and detener can refer to taking someone into custody, arrestar is more specifically used in legal and formal contexts of law enforcement making an arrest. Detener, on the other hand, has a broader application, meaning to stop or detain someone or something, which includes but is not limited to formal arrests.