The word 'unchaperoned' is built upon the noun 'chaperone,' which entered English from French in the 14th century. Originally meaning a protective hood or cape, 'chaperon' evolved metaphorically to denote an older person who accompanies and supervises young people in social situations, providing a figurative "cover" for propriety. The prefix 'un-' (a common Germanic negation) and the adjectival suffix '-ed' (indicating a state) were later added to create the modern adjective. Thus, the literal morphemes combine to describe the state of being without the protective oversight once symbolized by a hooded escort.

Structure: un (not) + chaperon (escort) + ed (adjective suffix) - un: A prefix of Germanic origin (Old English) meaning "not," used to form negatives. - chaperon: The core word, derived from Old French 'chaperon' meaning "hood" or "protector." - ed: A suffix of Germanic origin (Old English) used to form adjectives from nouns or verbs, indicating a state or condition.