1sign and accept liability under (an insurance policy), thus guaranteeing payment in case loss or damage occurs: the policy, underwritten at Lloyd’s, indemnifies trustees against loss arising from wrongful acts (as noun underwriting)the individuals whose assets support underwriting at Lloyd’s accept (a liability or risk) under the terms of an insurance policy: the insurance companies have underwritten just over half the risk
2(of a bank or other financial institution) engage to buy all the unsold shares in (an issue of new shares): the purchase is being paid for by a share issue, which has been underwritten undertake to finance or otherwise support or guarantee (something):they were willing to underwrite, in part, the construction of a ship
3 archaic write (something) below something else, especially other written matter: each subscriber should underwrite his reason for the place he allots his candidate
