Lewis Short
(adj.adv.) : incunctābĭlis, e, adj.2. in-cunctor
* That admits of no delay: illud quoque incunctabile est, ut, etc.,Dig. 22, 5, 21.—Hence, adv.: incunctābĭlĭter, unhesitatingly, without delay, Alcim. Sent. ad Phil. 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary