I have a question about meaning of "lover".

Is this word "Lover" usually used for sexual relationships??
There is no difference about meaning, between lover and significant other (also girlfriend/boyfriend) from English-Japanese dictionary...
If I had a girlfriend and I really like her because of her personality, should I not say "she is lover"??
will she be in a bad mood??

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 Hello Tomoya, and welcome:

 Indeed, a  friend, and a girlfriend,  would be  generally offended if you referred to them as your "lover" because  its connotation is that you are physically active with the person.  To love a person, does not mean that we are a "lover".  A "lover" is a sexual partner.  To  inform the general public that someone is your "lover" or that you are theirs, is  an aggregious breech of social ettiquette.

 That's like  Kiss---and---Tell.  A gentleman,  never tells others,  about his intimacy with another.

 Of course, not all are Gentlemen or Ladies either.  Some people babble  about all of their most intimate experiences. That is why the experiences are regared as profane, rather than sacred.

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