For ''iracundus'' I would suggest 'irascible/choleric/irritable' rathet than irritated. The descendant of that Latin adjective still exists in Italian (iracondo) and seems to have retained the original meaning. But it depends on the context, as Scholiast wrote.
Not being too familiar with British idioms, dear Scholiast, I'd like to know what the exact meaning of 'cross' is. Is it 'angry' or is it 'irritable'? (for iracundus, the latter would look correct to me). Thank you in advance.