Lenders protected themselves by demanding a "haircut" - collateral in cash or securities that exceeded the loan amount by a specified percentage.

贷款机构为了自身安全，会要求一个超出贷款金额一定百分比的“折幅”，质押现金或证券。

youdao

So presumably, if the deal is allowed to proceed, the ECB will ensure that all the risk actually remains with Bankia and the Spanish government - and therefore with Spanish taxpayers - by imposing a massive discount (or haircut) on the amount of cash it would exchange for the bonds.

BBC: No magic potion for eurozone banks

As a 46-year old male of the species with a dwindling amount of hair on my head, the opportunity to get a haircut that makes me feel like I rock is quite enticing I must say.

FORBES: Supercuts Rocks Out Their New Campaign