* Accidentally: This is the most direct opposite, indicating something happened by chance or without intention.
* Unintentionally: This is similar to accidentally but emphasizes the lack of intention rather than the specific cause.
* Carelessly: This suggests a lack of attention or thoughtfulness, often resulting in an unintended consequence.
* Negligently: This implies a failure to exercise reasonable care, often leading to a harmful or undesirable outcome.
* Involuntarily: This refers to an action that is performed without conscious control or intention.
Example:
* "He purposely broke the vase" (intentional).
* "He accidentally broke the vase" (unintentional).
* "He carelessly left the door open" (lacking attention).
* "He negligently drove through a red light" (failure to exercise care).
The best opposite word for "purposely" will depend on the specific situation and what you want to emphasize.