The word 'unrevealing' is a modern English formation built upon the well-established verb 'reveal.' Its core, 'reveal,' originates from the Latin revelare, which literally meant "to pull back the veil" (re- "back" + velum "veil, covering"). This vivid metaphor for disclosure entered English through Old French. The addition of the negative prefix 'un-', a staple of the Germanic linguistic tradition, directly inverts the meaning to "not disclosing." Finally, the participial '-ing' suffix transforms the verbal idea into an adjective describing a state or quality, completing the logical construction of a word that denotes a deliberate or inherent lack of disclosure, whether of information or physical form.

Structure: un (not) + reveal (show) + ing (adjective suffix) - un: A prefix of Germanic origin (Old English un-), meaning "not." It is a highly productive negative prefix in English. - reveal: A verb from Latin revelare ("to unveil, disclose"), via Old French reveler. It is composed of re- ("back, again") and velare ("to cover, veil"). - ing: A suffix from Old English -ende or -ing, used to form present participles and adjectives from verbs, indicating a quality or state.