Australian Slang
suffix used:
1. in colloquial abbreviations, as 'arvo' = afternoon; 'combo' = combination; 'commo' = communist; 'compo' = compensation; 'demo' = demonstration; 'kero' = kerosene; 'metho' = methylated spirits;
2. refer to a person: a) in a particular occupation, as 'bottle-o' = bottle collector; 'garbo' = garbage collector; 'journo' = journalist; 'milko' = milk vendor; 'scripto' = scriptwriter; b) of particular habits, as 'weirdo' - one whose behaviour borders on perversion or eccentricity; 'wino' = wine addict;
3. in colloquial responses showing compliance or agreement, as 'goodo', 'righto'; II. O - (sport) offence

English dialects glossary. 2013.