clamp down

Collins Concise English Dictionary © HarperCollins Publishers::

clamp down verb (intr, adverb) often followed by on:

1. to behave repressively; attempt to repress something regarded as undesirable

noun clampdown

1. a sudden restrictive measure

WordReference Random House Learner's Dictionary of American English © 2026

clamp /klæmp/   n. [countable]

1. a device for fastening two things together:
   Adjust the clamp to hold this piece of wood while I drill a hole here.

v. 

2. to fasten with a clamp or as if in a clamp:
   [~ + object] He clamped the glued pieces together for a stronger bond. I clamped my mouth shut and said no more.
3. clamp down, [~ + down (+ on + object)] to impose stricter control:
   to clamp down on crime.

WordReference Random House Unabridged Dictionary of American English © 2026

clamp  (klamp), n. 

1. a device, usually of some rigid material, for strengthening or supporting objects or fastening them together.
2. an appliance with opposite sides or parts that may be adjusted or brought closer together to hold or compress something.
3. one of a pair of movable pieces, made of lead or other soft material, for covering the jaws of a vise and enabling it to grasp without bruising.
4. Also called clamp′ rail′. [Carpentry.] a rail having a groove or a number of mortises for receiving the ends of a number of boards to bind them into a flat piece, as a drawing board or door.
5. [Naut.]
   • a horizontal timber in a wooden hull, secured to ribs to support deck beams and to provide longitudinal strength.
   • See mast clamp. 

v.t. 

6. to fasten with or fix in a clamp.
7. clamp down, to become more strict:
   There were too many tax loopholes, so the government clamped down.
8. clamp down on, to impose or increase controls on.

• Middle Dutch clampe clamp, cleat; cognate with Middle Low German klampe
• Middle English (noun, nominal) 1350–1400

Synonyms

• 6. clinch, clench, secure.