You can see the Queen of Swords as a woman with the following qualities or, if the the question concerns a man, as the female part of his psyche. But I tend to reading the queens as the inward side of a person (philosophy of life, attitude towards life, values, habitus, typical moods...), no matter whether this person is female or male.
The Queen of Swords is an intelligent, witty woman who in many cases has known great suffering. Mental independence means everything to her; to gain it she will even seal herself off from her feelings. This is why many people will think her cool or even cold. The Queen of Swords strives for insight and clearness; opacity and entanglements are an abhorrence to her.
She is problematic especially if she does really become cold and calculating and if she is so caught in her intellectual hights that she completely shuts out the physical and emotional reality.