It's what you say when you meet someone unexpectedly such as: "Hey Joe"
"What's up. It's a small world isn't it?"
something or someone insignificant. An inconsequential amount
It means that the world has endless possibilities.
It means someone is telling you a small hint to remind you of something
It means that you feel euphoric and totally optimistic.
Getting places is no idiom that I've heard of. Going places is an idiom. It means you are successful, moving up in the world.
It means you should be willing to risk a small amount in order to get a larger amount back.
It means by a very small margin, as in "it was nip and tuck whether we would win the game or not."
It's not really an idiom. It means "what are you thinking about."
It is not an idiom, it means your nose is itching.
RFP is not an idiom. It's an abbreviation.
Probably you mean "mundo". This is the world. Common idiom is "todo el mundo" - literally "all the world", but is interpreted as everyone or everything.
"Sieve" is not an idiom. See the related link.