Free Rider
Plain definition
A free rider is someone who benefits from a good or service without paying for it, which is possible when the good is non-excludable.
In economics
The free-rider problem explains why markets underprovide public goods and why voluntary contributions fall short: each person prefers to let others pay. It also appears in group work, alliances, and tax evasion.
Example
If a neighborhood funds a shared park through voluntary donations, residents who skip donating but still use the park are free riders.
Common confusion
Free riding is not theft in the legal sense; the good is non-excludable, so non-payers cannot be stopped — the problem is the underfunding it causes, not a crime.