Black rats, that means bad luck. Black cats, ditto. Bad Omens could also be, like, some people consider shooting stars bad omens, some people consider blondes bad omens, (not a lot of people, though), but it's a form of opinion, some people don't even believe in omens.
bad omens yet to come
Good omens were signs of positive outcomes for future actions. The Romans practiced augury, which was a religious cult of reading the omens of the gods. Bad omens signalled that the gods did not approve of the future action. There were many techniques for reading the omens of the gods and there were all sorts of signs.
No. The very concept of "bad omen" is unscientific.
We were planning for a picnic, but the dark clouds seemed like a bad omen.
Calpurnia's dream, the soothsayer's prophecy, the bad weather.
Full of omens or portents; something which suggests that something bad is soon to happen.
Because of her nightmare, the bad omens and the augerers results
No there has been no bad omens from flinging sparrows.
No, that is just a superstition. Black crickets are just as lucky as any other organism.
Cassius is concerned about the eagles being replaced by kites and ravens.
Yes, it is considered very bad luck to see your doppelganger. It is believed if you see it you will suffer death or very serious injuries as they are referred to as bad omens.