Some key words for the three of swords are heartbreak, rejection, delays, sorrow, unhappiness and grief.
The three of swords is card that you really don’t want to see in a reading because it indicates heartbreak and sorrow. In a relationship reading, the three of sword might indicate a relationship break up that is felt not only physically but mentally at a very deep level. However, understanding what caused the pain, accepting it and working through the pain can help you recover.
When the three of swords appears reversed in a reading, it indicates that although you have experienced some form of heartbreak, you are not at the point where you are starting to recover. Oddly enough, the three of swords can also indicate that you may not be doing the work that you need to for yourself and are at the risk of becoming stuck in your sorrow and pain.
Want a more comprehensive interpretation of the 78 tarot cards which includes the three of swords. I highly recommend “The Ultimate Guide to Tarot Card Meanings”, by Brigit Esselmont.