Sentence:  For centuries it has been the rule that a mortgagor's equity of redemption cannot be <WSD>clogged</WSD> and that he cannot, as a part of the original mortgage transaction, cut off or surrender his right to redeem. Any agreement which does so is void and unenforceable sic as against public policy. 
Meaning of the word marked with <WSD> tags:  To enforce a mortgage lender right that prevents a borrower from exercising a right to redeem.