Detroiters, now erecting a Robocop statue as a half-joking, half-serious morale boost, may want to consider bronzing Mulally next.
mid-15c., "expressing earnest purpose or thought" (of persons), from Middle French sérieux "grave, earnest" (14c.), from Late Latin seriosus, from Latin serius "weighty, important, grave," probably from a PIE root *swer- (4) "heavy" (cf. Lithuanian sveriu "to weigh, lift," svarus "heavy;" Old English swære "heavy," German schwer "heavy," Gothic swers "honored, esteemed," literally "weighty"). As opposite of jesting, from 1712; as opposite of light (of music, theater, etc.), from 1762. Meaning "attended with danger" is from 1800.
serious se·ri·ous (sēr'ē-əs)
Being of such import as to cause anxiety, as of a physical condition.