From Longman Business Dictionary
negotiablene·go·ti·a·ble /nɪˈgəʊʃiəbəl, -ʃə--ˈgoʊ-/ adjectiveadj1BANKING a negotiable document, such as a BANKNOTE or a BILL OF EXCHANGE, can be exchanged for money or goods 2COMMERCEan offer, price etc that is negotiable can be discussed and changed before being finally agreed onThe terms of the contract are not negotiable.
→ opposite non-negotiable —negotiability noun [uncountableU]the negotiability of international bills of exchange