Quick Answer: The title of Complete Unknown comes from the classic Bob Dylan song "Like a Rolling Stone," which is itself derived from the famous proverb, "A rolling stone gathers no moss." Alice, the film's protagonist, is essentially a rolling stone; she is a vagabond who constantly changes her identity, avoiding responsibilities and hurting loved ones along the way. Complete Unknown may initially seem like the tale of an elusive femme fatale—a rootless and free rolling stone—but the film reveals a truly tragic character behind the title. 

The drama-thriller Complete Unknown (2016) is a character study of a woman with an enigmatic past and a proclivity for stretching the truth. Complete Unknown provides interesting commentary on the ambiguous nature of identity and the perpetual struggles that humans must endure in order to escape the past and reinvent themselves. The film’s plot follows Alice (Rachel Weisz), a beautiful yet mysterious woman who revisits an old flame (Michael Shannon) at his birthday dinner party. As soon as the former lovers reconnect, the secrets surrounding Alice begin to unravel, ultimately taking the movie in a unique and unknown direction.

Rachel Weisz as Alice in Complete Unknown

Many critics have noticed that the title of Complete Unknown comes from the classic Bob Dylan song “Like a Rolling Stone”. As the chorus of the song famously goes: “How does it feel?/To be without a home?/Like a complete unknown?/Like a rolling stone?” The title of “Like a Rolling Stone” itself is actually derived from the well-known proverb, “A rolling stone gathers no moss,” credited to Latin writer Publilius Syrus. Syrus wrote that the proverb specifically applies to “people who are always moving, with no roots in one place or another, avoiding responsibilities and cares.” At the time, Syrus was referring to the nomadic tribes that were prevalent in the ancient Middle East.

However, the meaning of the proverb is still heavily applicable to Rachel Weisz’s Alice. Alice is, essentially, a rolling stone. In the opening minutes of the film we are introduced to Alice’s shifting array of disguises: one as a hipster botanist, another as an assistant to a Chinese magician, and another as a nurse in a trauma unit. We learn from the first few minutes of the movie that she is constantly moving and changing her identity as soon as she grows tired of it. “I realized I could be anyone I wanted,” she tells Tom, her former lover. “I could live a thousand lives.” In taking on the persona of multiple anonymous identites, Alice is altogether many and no one at the same time. She travels around the world as a vagabond, where both everywhere and nowhere is her home.

Rachel Weisz as Alice in Complete Unknown

As the film’s plot unfolds, we discover more about Alice and what’s underneath her aloof and captivating exterior. Alice is a protagonist constantly looking to reinvent herself, yet she is unable to avoid the inextricable hold that the past has on her. “When everyone comes to know who you are, you’re trapped,” Alice remarks at one point in the film. The act of reinventing oneself and starting over again is a romantic and alluring concept. After all, the proverbial "moss" may represent stagnation, boredom or monotony. But a rolling stone that gathers no moss also avoids becoming rooted or making connections, and this is certainly true of Alice. She has caused a troubling amount of emotional damage to her loved ones by walking out on them, including Tom. Though Alice may have yearned for the proverb-inspired title's more adventurous, nomadic meaning, she comes to learn that to be a rolling stone is a lonely existence. Complete Unknown may initially seem like the tale of an elusive femme fatale, but the film reveals a truly tragic character behind the title.