There are multiple definitions - click on the translation that matches your context.

扣押

动词

full

detain

verb

Definitions of detain

English

to delay someone for a short period of time

Apologies for being so late, I was unavoidably detained.

English

to force someone officially to stay in one place so that they cannot leave

Police have detained two people over an alleged plot to extort money from grieving actor John Travolta.