The word 'uncomprehending' is a modern English formation built upon the verb 'comprehend'. 'Comprehend' itself originates from the Latin comprehendere, a compound of com- (together, completely) and prehendere (to seize, grasp). This literal sense of physically grasping evolved metaphorically in Latin to mean "to grasp with the mind, to understand." The English verb was formed in the late 14th century. The adjective 'uncomprehending' was later created by adding the native English negative prefix 'un-' and the participial suffix '-ing' to this Latinate base, resulting in a word that literally means "not in the state of understanding." This logical construction allows it to describe a person or expression that shows a complete failure to mentally grasp or seize the meaning of something.

Structure: un (not) + comprehend (understand) + ing (adjective suffix) - un: A prefix of Germanic origin (Old English un-), meaning "not," used to form negatives. - comprehend: A verb from Latin comprehendere, meaning "to grasp, seize, understand." In this word, it is used as a base. - ing: A suffix of Germanic origin (Old English -ende, -ing), used to form present participles and adjectives indicating a state or quality.