Common Words:
* Accuracy - the quality of being accurate
* Advocacy - public support for or recommendation of a particular cause or policy
* Capacity - the ability or power to do, experience, or understand something
* Conspiracy - a secret plan by a group of people to do something unlawful or harmful
* Democracy - a system of government by the whole population or all the eligible members of a state, typically through elected representatives
* Diplomacy - the practice of conducting negotiations between representatives of states or organizations
* Efficacy - the ability to produce a desired or intended result
* Infancy - the state of being a baby or a very young child
* Legacy - something handed down from the past, as from an ancestor or predecessor
* Privacy - the state or condition of being free from being observed or disturbed by other people
* Sufficiency - the state or quality of being enough or adequate
* Vacancy - the state of being empty or unoccupied
Less Common Words:
* Adjacency - the state of being next to or adjoining
* Agency - the capacity, state, or quality of acting or of exerting power
* Auspices - patronage, support, or guidance
* Clandestinacy - the state of being secret or concealed
* Delinquency - the state of being a delinquent
* Discrepancy - a lack of compatibility or similarity between two or more facts
* Enthusiasm - intense and eager enjoyment, interest, or approval
* Flamboyancy - the quality of being flamboyantly showy
* Intricacy - the state of being intricate
* Latency - the state of being latent
* Obstinacy - the quality of being obstinate; stubbornness
* Perniciousness - the quality of being pernicious
* Relevancy - the quality of being relevant
* Tenacity - the quality of being tenacious
* Transparency - the quality of being transparent
This list is not exhaustive, but it provides a good starting point for exploring words that end in "-acy."