in138MEANING AND DEFINITION OF NI. The word ‘negotiable’ means transferable from one person to another, and the term ‘instrument’ means a document of title of money (as described by Prof. Goode).. A NI is required toProcess of complaint in Cheque Return Case under Section 138 of Negotiable Instruments Act. 1. Demand Legal Notice, 2. File Complaint in the Court under section 138 of NI Act, 3. Sworn