What is the difference between a thief and a robber?
My dictionary says:
robber is a person who illegally takes something from a person or place
thief is a person who steals things
So, could you please tell me what is the key difference between these two?

UPD.: one more mishmash.. What is the difference between to jump and to leap?

Thank you!

P.S.: Would it be correct to say that "a robber steals with force, brutality and intimidation. Unlike a thief, who often times does not come to contact with the person he/she steals from. More of an assailant then anything?"

Question

What is the difference between a thief and a robber?
My dictionary says:
robber is a person who illegally takes something from a person or place
thief is a person who steals things
So, could you please tell me what is the key difference between these two?

UPD.: one more mishmash.. What is the difference between to jump and to leap?

Thank you!

P.S.: Would it be correct to say that "a robber steals with force, brutality and intimidation. Unlike a thief, who often times does not come to contact with the person he/she steals from. More of an assailant then anything?"

Answer

A thief usually steals secretly and the victim usually becomes aware of the theft only after something has been stolen.

A robber is not only usually seen by the victim, but also often injures or threatens to injure the victim (or use some other type of force) during the robbery.

Answer

To jump and to leap are pretty much the same to me.
Though to jump is more frequent in usage than to leap.
Here's a sentence with both terms : "Basketball players increase their vertical leap to jump higher"

Answer

In casual conversation, the two words are used almost interchangeably.   In a court of law, with a judge and lawyers and stuff, there's an important difference.  But if I'm talking to my friends, I will use either term and mix them up in the same statement even.  So, yes, your PS is correct, but native speakers are probably not making that distinction when they speak.

A leap is more graceful and poetic than a jump.   A newspaper will report that a woman "jumped."  A novelist will write that the same woman "leapt."

Answer

Reply to your PS question : 
Yes, It would be correct to say so.