Lewis Short
(adj.adv.) : irrĕcūsābĭlis (inr-), e, adj. 2. inrecusabilis
* Not to be refused (post class.): occasio,Cod. Just. 3, 1, 13; Hier. Ep. 60, 14. —Hence, adv.: irrĕcūsābĭlĭter, without possibility of refusal, Rustic. c. Aceph. p. 1218.
Charlton T. Lewis, Charles Short, A Latin Dictionary