E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The beggar of gigantic stature, who kept watch over the suitors of Penelope. His real name was Arneos, but the suitors nicknamed him Iros because he carried their messages for them. Ulysses, on his return, felled him to the ground with a single blow, and flung him out of doors.
Poorer than Irus. A Greek proverb, adopted by the Romans (see Ovid), and existing in the French language (Plus pauvre quIrus), alluding to the beggar referred to above.