Common Words:
* Accuracy
* Apathy
* Capacity
* Currency
* Democracy
* Efficiency
* Frequency
* Infancy
* Lunacy
* Mercy
* Policy
* Privacy
* Sufficiency
* Tendency
* Vacancy
Less Common Words:
* Acrimony
* Adjacency
* Agency
* Arduousness
* Celerity
* Conciseness
* Conspiracy
* Decency
* Emergency
* Enormity
* Exactitude
* Fluency
* Fragility
* Galaxy
* Granularity
* Hierarchy
* Hostility
* Immensity
* Insanity
* Legitimacy
* Necessity
* Obscenity
* Obstinacy
* Promiscuity
* Redundancy
* Resiliency
* Sanguinity
* Simplicity
* Specificity
* Transparency
* Utility
* Vulnerability
This is not an exhaustive list, but it provides a good starting point. Keep in mind that the suffix "cy" is often used to create nouns from adjectives, so you can use this knowledge to come up with more words.
For example, the adjective "accurate" becomes the noun "accuracy".