Clue: Primarily unrealistic? Thomas once pictured it acerbically! (6)
Answer: UTOPIA
Explanation: Primarily unrealistic? Thomas once pictured it acerbically! (6)
Everyman's trademark 'primarily' clue. – '**U**nrealistic **T**homas **O**nce **P**ictured **I**t **A**cerbically'. 'Thomas' is , who coined the word for his book of the same name.