to feel out = to try to understand a situation or person without asking direct questions; to just try to see what it is without asking anyone. the vibe = the ambience of a place OR the feeling you feel because of a person, or in relation to them. What the others have written is helpful! But I hope this clarifies.

‘it’s a vibe’ means ‘it’s a feeling, it’s a sensation.’ So, maybe I walk into a place I’ve never been before and somehow something feels ‘off’ to me. I might say, ‘It’s just a vibe but I don’t want to stay here.’ Or I get a call from an old friend and I get a vibe … maybe a good vibe, maybe a bad vibe. If it’s a good vibe, it’s a pleasant feeling or sensation; bad vibe: not pleasant.

This expression is colloquial. Imagine you are with friends in the evening in a section of town that has lots of night life (clubs, bars, etc.) One place looks interesting as a possible place to spend some time, but you are not sure yet if you will like it. You say to your friends, "let's go in for just a while and feel out the vibe". If the vibes "check out", you stay. If not, you start looking for another place.

This is hard to explain, and I hope you get more answers than just mine. "Vibe" is something like the feeling of a place, person, organization, etc. If you say a person gives you "bad vibes", it means you get a bad feeling from him. It's the same with any person, place, or thing. To "feel out the vibe" of something is to try to determine what feeling or "vibe" you get from that person, place, or thing. In very basic words, it means you get a sense of whether the person/thing/group/etc is good or bad, or possibly something more complex. "Vibe" CAN have a more complex meaning, but that meaning would be determined by context. It always means the sense one gets of something. Is it good or bad. Do they like me or not. Do they welcome newcomers or not? It's things like that. It's things you can feel.