restrainer

1. 1. To hold back or keep in check; control: couldn't restrain the tears.

   2. To hold (a person) back; prevent: restrained them from going.

2. To deprive of freedom or liberty.

3. To limit or restrict.

Synonyms: These verbs mean to hold back or keep under control. Restrain implies restriction or limitation, as on one's freedom of action: "a wise and frugal government, which shall restrain men from injuring one another" (Thomas Jefferson).
To curb is to restrain as if with reins: "You might curb your magnanimity" (John Keats).
Check implies arresting or stopping, often suddenly or forcibly: "a light to guide, a rod/To check the erring" (William Wordsworth).
To bridle is often to hold in or govern one's emotions or passions: I tried with all my might to bridle my resentment.
Inhibit usually connotes a check on one's actions, thoughts, or emotions: A fear of strangers inhibited his ability to travel.