unsubscriber means one who unsubscribes. Lexicurio rates it Sui generis — a strength score of 86 out of 100.
Etymology
From unsubscribe + -er or un- + subscriber.
noun
- One who unsubscribes.“It is also important to find out why readers unsubscribe from the blog. If the organization has the unsubscriber's e-mail address, it should send a follow-up email and a minisurvey asking why the person chose to unsubscribe.”