The word 'ungraded' is a modern English formation built from a Germanic prefix and a Latin root. The negative prefix 'un-' is attached to the past participle 'graded,' which itself derives from the Latin noun 'gradus' (step, degree). The core concept of 'gradus' relates to a step on a ladder or stage in a progression, which evolved into the academic sense of a level of achievement or quality. Therefore, 'ungraded' literally means "not having been assigned a step or degree (of evaluation)," directly leading to its modern meanings of not receiving a score or not being organized into levels.

Structure: un (not) + grad (step, degree) + ed (adjective suffix) un: A prefix of Germanic origin (Old English 'un-'), meaning "not." It functions as a negative particle. grad: A root from Latin 'gradus,' meaning "step" or "degree." It functions as the core semantic element. ed: A suffix from Old English '-ed,' '-od,' used to form adjectives from nouns or verbs, indicating possession of a quality.