1. Noun. Boyo is slang for boy or lad or mate. Used mostly by English, Irish and Welsh males. (Maybe by the Scottish as well; but who can understand what those cunts are saying?) In the plural format, boyos can refer to a woman's breasts, especially if they are of immodest size.
You're some boyo, ya cunt ya, pissin' all over that poor girl's closet.
Boy oh boy oh boy. Check out the boyos on yer one over there. A man could sprain a wrist.
My mother has some set of boyos on her.
Sis, bring out the boyos for the lads.
Mum, I'm thirsty. Take out the boyos and give us some tit.