General synonyms:
* Reduction
* Decrease
* Abbreviation
* Limitation
* Restriction
* Abridgement
* Diminution
* Shortening
* Retrenchment
* Contraction
More specific synonyms:
* For budgets: Cutback, austerity, paring down
* For rights: Suppression, infringement, erosion
* For activities: Suspension, postponement, cessation
* For freedom: Impediment, restraint, suppression
More formal synonyms:
* Abatement
* Circumspection
* Truncation
The best synonym to use will depend on the specific context and what you want to emphasize.