Green’s Dictionary of Slang

dig n.3

also otium dig
[Lat. otium cum dignitate, the dignity of leisure, popularized in Cicero, Ad Familiares, I.xi.21]


[US]L.H. Bagg Four Years at Yale 44: Dig, [...] an abbreviation for dignity.
[Aus]Sun. Times (Perth) 18 Feb. 4/7: I ’ad a nappointment with me girl. Jim coulder come too [...] But ’e stood on ’is dig.
[UK]J. Ware Passing Eng. of the Victorian Era 109/1: Dig (Mid. Class, Elegant). Abbreviation of ‘dignity’; e.g., ‘So I stood upon my dig, and told him his room was nicer than his company.’ Sometimes ‘otium dig’ (from ‘otium cum dignitate’; e.g., ‘Come and see me in my summer-house; there I am in my otium dig.’.
[Aus]Bulletin (Sydney) 5 Aug. 47/2: ‘That’s no way fer a gentleman ter speak ter a lady,’ says May, on ’er dig. at once.