(5 syl.). Insouciant, devil-may-care, easy-go-lucky. As the “Pococurante Guardsman” (the imperturbable and impassive ...). Also used for one who in argument leaves the main gist and rides off on some minor and indifferent point.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Pococurante from Infoplease: