ἐξὸν [7 verses] (part sg pres act neut acc) "Is it lawful" is exesti, which means "to be allowed," "is possible," and "to be in one's power." -- "It is lawful" is a verb, which means "it is possible" and "it is allowed." It generally refers to something within someone's power, or, in this case with the negative, something outside of someone's power. This word does not, as it might seem, refer directly to Biblical law.