Tawriya is defined as concealing, and it could be called “creative lying”. It is OK to break the intent of the oath, as long as you don’t break the letter of the oath. (Reliance of the Traveler, sections o19.1 and o19.5)
For example: suppose someone protests that surah 1 of the Koran demeans Christians and Jews, because it is a supplication Muslims make to Allah seventeen times a day to keep them from the path of “those with whom God is angry” and “those who have lost their way”.
A Muslim might respond: “surah 1 never mentions Jews or Christians”. He is practicing tawriya, because while surah 1 does not mention Jews and Christians by name, he knows full-well that the word “those” refers to Jews and Christians.
Another example: when a Muslim responds to your greeting of “Merry Christmas!” He might say, “I wish you the best.” In your mind, you think he has returned a Christmas greeting. In actuality, he has expressed his wish for you to convert to Islam; he wishes the best for you which, in his view, is becoming a Muslim.