To do a proper translation, the meaning of the words as components of a sentence must be carefully discovered and this requires the translator to use the knowledge of semantics. In order to gain the meanings of the Quranic vocabulary, Izutsu explores their meanings in pre-Islamic so-called ignorant-era poetry by employing seven methods contextual definition, word substitution, antonyms, semantic field, negative form of words, synonymy of expressions and usage in non-religious context. This descriptive-analytical research semantically examines the word "rayb (lit. doubt)" using the first four methods applied by Izutsu. This research found that the word "rayb" having come along with “manoon”, "events", "time" and "aeon" means hard events, death, unpleasant events, and so on. But in the Qur'an, the phrase "rayb al-Manoon" appears only once. Among religious and doctrinal concepts, the word “rayb” has different uses in the Qur'an, the true meaning of which is “doubt through enmity and hatred”. Therefore, in order to fully transfer the semantic units to the target language, the descriptive sequence ‘spiteful’ has been proposed for it.