Half jocular, half serious; partly in jest and partly in earnest; blending jokes and serious matters.
Combined form of joco-, from the Latin jocus, (joke, jest) + serious.
1885 E. Johnson in Browning Society Papers vii. 29:
Our own poet has lately characterized himself as a jocoserious genius; and in fact this jocoseriosity seems of much the same quality with the eironeia of the Greek.
While at the pub last night, a particularly goat-drunke person was endeavoring to chat up a friend's girlfriend. When my friend found out, he warned the gentleman, in a very jocoserious manner, that if he continued to try and kiss jhis girl then he would tear off his charlies and drop them in the nearest jug of cheap Sangria.
He declined to further advance his efforts. :D