1. without authority :

2. of laws and contracts, invalid , ἄκυρον ποιεῖν, Lat. irritum facere, to set aside, and ἄκυρον γίγνεσθαι, to become of no force , to be set aside, (Plato Philosophus); νόμοις ἀκύροις χρωμένη, i. e. having laws, but not enforcing them, (Thucydides)

3. of persons, having no right or power , ἄκ. ποιεῖν τινά (Xenophon Historicus); with genitive, ἄκυροι πάντων γενήσεσθε (Demosthenes Orator) (ML)