An examination of the doubts raised against the Qur'an shows that the source and axis of many literary debates is the lexical type of the words of the Qur'an; Therefore, the present article intends by examining some doubts that are centered on lexicology, by the method of description and analysis, emphasizing the need for research in linguistic and Quranic terminology and using the correct and sound rules of lexicology for interpretation of the Qur'an and to answer to doubts. In this study, it was found that the source of the doubts of the three-day fast of Ramadan, the incompatibility of human creation with scientific discoveries about the combination of jumping water from the bones of the man's back and the middle of the woman's breasts, and the doubt of incompatibility of Jesus' speech in the cradle based on the Christian sources, rooted in Lack of correct knowledge of the meaning of the words "Yutiqunah" and "Ayyaman Ma'ududat" in verse 184  of Baqarah, "Tara’ib" in verse 7  of Tariq and "Sabiyy" in verse 29  of Surah Maryam, and can be relied on by using lexical sources. The Qur'an itself and the choice of meaning according to the scientific and historical facts of these words from among their various meanings, answered the mentioned doubts.