de·tain / diˈtān/ • v. [tr.] keep (someone) in official custody, typically for questioning about a crime or in politically sensitive situations: she was detained without trial for two years. ∎  keep (someone) from proceeding; hold back: she made to open the door, but he detained her.DERIVATIVES: de·tain·ment n.

detain XV. repr. tonic stem of (O)F. détenir (AN. detener) :- Rom. *détenēre, for L. dētinēre, f. DE- 2 + tenēre hold.
So detainer (leg.) detention XVII. — AN. detention XV. — F. or late L.