It is an act of pursuing the third party on behalf of the policyholder after paying the claim amount. The insured here gets his payment on time in case of a claim and the insurance company reimburses the same amount from the third party who may have caused the impairment.
Policyholders, when acquainted with this term ‘Subrogation’, will instantly think that this is one term and is beneficial only for insurance companies, but it is surprisingly and indirectly beneficial to the insured. Some insurance companies add the deductible amount too in the case of a subrogation. So, in case of such a situation where the damage is done by the third party, you get your claim amount plus the deductible once the third party pays the compensation to the insurance company.
This is in no way a hidden process; your insurer will be transparent to you. You will be given the record of the amount it paid you for your claim and the amount they are reimbursed from the third party as a subrogation claim.