What is characterized as an incomplete instrument?

An incomplete instrument is best defined as a document, particularly a financial instrument like a check, that lacks essential elements necessary for it to be considered valid and enforceable. In the context of this question, a check that has been signed but left blank is clearly an incomplete instrument since it does not specify the amount that can be drawn from the account. This lack of a filled-out amount means the check cannot be properly executed or cashed, making it incomplete.

In contrast, a fully signed check contains all the necessary information—signature, date, and amount—allowing it to be processed and accepted as a valid form of payment. An installment payment plan, while it may involve agreements and signatures, does not fall under the category of an incomplete instrument in the context of checks and financial documents. A canceled check is one that has been processed and marked as paid, thus no longer qualifies as incomplete since it has fulfilled its purpose and is no longer negotiable.