Voluntary
Definition 1 of 4
Pro Tip 1/3
Personal Choice
Stresses that the action is taken by someone's own decision, without pressure. He took on the project on a voluntary basis.
Pro Tip 2/3
Positive Nuance
Carries a positive connotation, suggesting generosity or goodwill. Her voluntary work with children earned her great respect.
Pro Tip 3/3
Not Compulsory
Implies that there is no legal or formal obligation involved. Attendance at the seminar is purely voluntary.