unaffiliated
adj.not connected to or part of a group, organization, or political party. You use this to describe someone who stands alone or is independent.
adj.not connected to, associated with, or a member of a specific group, organization, or political party. Often used to describe independent candidates or neutral entities.
“He is an unaffiliated candidate running for mayor.”
“The local chapter of the union is unaffiliated with the national organization to maintain its own unique policies.”
“While many small businesses are part of a larger franchise, this particular shop remains unaffiliated, allowing it to retain full creative control over its product line and customer service approach.”
“Kidder/Yale University Art Gallery/Wikimedia Commons By many measures, Americans are growing less religious : Since 2007, for example, the percentage of people who pray daily has dropped, while the “unaffiliated” have grown to 29%.”
From un- + affiliate + -ed.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.