lawful
adjective
1 the jury delivered a verdict of lawful killing:
legitimate, legal, licit, just, permissible, permitted, allowable, allowed, rightful, proper, constitutional, legalized, sanctioned, authorized, warranted, justified, justifiable, approved, recognized, admissible, above board, within the law, going by the rules;
informal legit, kosher, by the book.
▷antonyms illegal, prohibited.
lawful Oxford Dictionary of English