seriously Pronunciation: /ˈsɪərɪəslɪ/Translate seriously | into German | into Italian | into Spanish French translation of seriouslyadv 1 [speak, think] sérieusement to take sb/sth seriously = prendre qn/qch au sérieux 2 [ill, injured] gravement; [underestimate] vraimentseriously in other Oxford dictionaries Definition of seriously in the British & World English dictionary Definition of seriously in the US English dictionary