还贷 means 'to repay a loan' and is a separable verb (离合词). The object 贷 can be separated from the verb 还 when inserting words like aspect markers (了、过), measure words (次), or duration (几年). For example: 还了一次贷 ('repaid the loan once'). The correct pronunciation for this sense is huán dài, though the input shows hái; be aware of this discrepancy.