n. one of the most significant words in the field of law, liability means legal responsibility for one's acts or omissions. Failure of a person or entity to meet that responsibility leaves him/her/it open to a lawsuit for any resulting damages or a court order to perform (as in a breach of contract or violation of statute). In order to win a lawsuit the suing party (plaintiff) must prove the legal liability of the defendant if the plaintiff's allegations are shown to be true. This requires evidence of the duty to act, the failure to fulfill that duty and the connection (proximate cause) of that failure to some injury or harm to the plaintiff. Liability also applies to alleged criminal acts in which the defendant may be responsible for his/her acts which constitute a crime, thus making him/her subject to conviction and punishment. Example: Jack Jumpstart runs a stop sign in his car and hits Sarah Stepforth as she is crossing in the cross-walk. Jack has a duty of care to Sarah (and the public) which he breaches by his negligence, and therefore has liability for Sarah's injuries, giving her the right to bring a lawsuit against him. However, Jack's father owns the automobile and he, too, may have liability to Sarah based on a statute which makes a car owner liable for any damages caused by the vehicle he owns. The father's responsibility is based on "statutory liability" even though he personally breached no duty. A signer of a promissory note has liability for money due if it is not paid and so would a co-signer who guarantees it. A contractor who has agreed to complete a building has liability to the owner if he fails to complete on time.