"lawful excuse" means having a valid reason that is allowed by law for doing something that might otherwise be considered wrong or illegal. Full definition
Finally, it should be noted that s. 86 (1) only creates an offence where a person is acting «without lawful excuse». (edelsonlaw.ca)
Daniel Walter Friesen of Aldershot, Kings County, has been charged with willfully without lawful excuse killing kittens; contrary to section 445 (a) of the criminal code. (spcans.ca)
Any person who, being charged with the duty of providing for another the necessaries of life, without lawful excuse fails to do so, whereby the life of that other person is or is likely to be endangered or his health is or is likely to be permanently injured, is guilty of a felony and is liable to imprisonment for three years. (kenyalaw.org)