from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An act or example of forceful regulation, repression, or restraint: a crackdown on crime.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Abruptly stern measures or disciplinary action; increased enforcement
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. severely repressive actions
Noun use of the verb “to crack down” (Wiktionary)