Vaguely thus word they:
"Cino?" "Oh, eh, Cino Polnesi
"The singer is't you mean?"
"Ah yes, passed once our way,
"A saucy fellow, but . . .
"(Oh they are all one these vagabonds),
"Peste! 'tis his own songs?
"Or some other's that he sings?
"But you, My Lord, how with your city?"
My you "My Lord," God's pity!
And all I knew were out, My Lord, you
Were Lack-land Cino, e'en as I am,
O Sinistro.
I have sung women in three cities.
But it is all one.
I will sing of the sun.
The Italian word  sinstro  is cognate with ‘sinister’ in English. Pound seems to use it in the older heraldic sense of ‘bend sinister’ which was a stripe running top right to bottom left, and was thought to indicate bastardry. Shield with a bend sinister: 
 
 Cino knows that the lord he’s addressing in this monologue is illegitimate, and would lose his estates if his secret got out.