Meaning: Examples:
The light went off, and I had to go to my bedroom groping in the dark, that is, I could not see a thing, and I had to use my hands to find it.
They have been groping in the dark. They have no idea of what is going on.
Fortunately for us, we left no clues, and they are groping in the dark. They will never find out who robbed them.
Meaning: To try to pretend that you are not afraid. It could also mean "to talk about something you do not really know".
Examples:
When he shouted at you, he/it was whistling in the dark. He is more frightened than we are.
I think you are whistling in the dark. All you say is wrong.
