The phrase "a second identity" is correct and usable in written English.
It can be used when discussing the concept of having an additional or alternative identity, often in contexts like psychology, online personas, or dual citizenship.
Example: "In the digital age, many people create a second identity to navigate social media platforms more freely."
Alternatives: "an alternate identity" or "a dual identity".
But away from network TV, he was developing a second identity.
Not much is known about Humberto -- whether that was his real name, whether he worked off the books or if he had bought a second identity.
For example, Tracy, a mentee of mine who had served a year in the Bedford Hills Correctional Facility for women, created a second identity that was a spoken word poet.
On another trip, the earnest accountant who picked us up turned out to have a second identity as a self-mutilating moon-dancer at the pyramids of Teotihuacán, near Mexico City.
Chaney's personality seems to dominate "The Blackbird," in which he stars as the title character, a London thief who hides his activities behind a second identity as the Bishop, the saintly director of a mission in the Limehouse district.
By day, Thom works as a project coordinator at a charity in south London, but for the last four years she has had a second identity as Touretteshero, spreading the word about the playful and creative side of this often misunderstood neurological condition.
After school, Jubilee (born Jerome Temple), 34, takes on a third identity: as coach.
A third identity relates thanatological age, chronological age, and lifespan, TAL.
A fourth identity relates lifespan, birth cohort, and death cohort, LCD.
This nostalgia, this sentiment, has created a third identity here: not fully Jewish (or Irish, or Italian, or Greek), and not fully American.
"She's probably got a whole second identity, which is why her credit cards and A.T.M. have been dormant".
