At least since the time of Westcott and Hort, the concept of explicitness has been used in the practice of New Testament textual criticism. However, until now, the concept has not been defined or tested. This article examines how explicitness has been understood and used by textual critics, and then outlines how linguistics can support the application of this concept in understanding textual transmission. It then tests the validity of the concept of explicitness for textual criticism in comparison to the results of applying traditional internal and external criteria. It also demonstrates the explanatory power of explicitness by evaluating select textual variants in the Gospel of John. It concludes that the use of explicitness for the evaluation of variants is linguistically coherent and text-critically valid and can assist in the identification of the most primitive reading.