n. The right to keep a person, or a person's goods or property, against his will. A type of custody.
the GNU version of the Collaborative International Dictionary of English
n. One who detains.
n.
n. The keeping possession of what belongs to another; detention of what is another's, even though the original taking may have been lawful. Forcible detainer is indictable at common law.
n. A writ authorizing the keeper of a prison to continue to keep a person in custody.
The Century Dictionary and Cyclopedia
n. One who withholds; one who detains, stops, or prevents from proceeding.
n. In law:
n. In law, the fact of being detained or held in custody: as, a writ of habeas corpus may issue to inquire into the detainer of a prisoner.
Word Usage
"A detainer is a request from ICE that the local jail hold the individual in custody for up to 48 hours during which ICE decides whether or not to assume custody of the person and initiate deportation procedures."