Step 1: Read the question.
We must find which of the four items is not a document under the Bharatiya Sakshya Adhiniyam, 2023. The choices are private papers, caricature, map and inscription.
Step 2: Know the meaning of a document.
Under the Act, a document means any matter expressed or described upon any substance by means of letters, figures, marks, symbols or other methods, meant to record or convey information. So the key idea is that a document records information.
Step 3: Test private papers.
Private papers carry written information. They record facts and details, so they are documents.
Step 4: Test maps and inscriptions.
A map records geographical information through marks and symbols, so it is a document. An inscription records information through engraved or written marks, so it too is a document.
Step 5: Test a caricature.
A caricature is mainly an artistic drawing made for satire, humour or illustration. Its purpose is artistic expression, not to record information. So it is generally not treated as a document in the legal sense.
Step 6: Conclude.
Since documents are records of information, and a caricature is an artistic expression rather than a record, the caricature is the odd one out. So the correct answer is caricature.
\[ \boxed{\text{Caricature}} \]