Русско-англо-русский юридический словарь

It is very common for commercial documents to contain provisions which limit the right of creditors to lodge proofs of debt in circumstances where doing so would compete with the rights of another creditor.

One of the most common examples is found in guarantees. It is often, if not invariably, the case that a bank providing credit to a Small-Medium Enterprise (“SME”) will require the director(s) of the corporate SME to give a personal guarantee of its obligations to the bank. Commonly the landlord of premises rented by the company will also require such a guarantee as indeed may suppliers and other creditors of the company. It is common for such guarantees to contain clauses which say that the guarantor may not (amongst other things) prove in competition with the bank, lessor or supplier (as the case may be). (ERA Legal)

Proving is the process by which a creditor seeks to establish its claim against the insolvent estate. A proof of debt is the document on which a creditor submits details of its claim. (Practical Law)