forty-five-year-old

The compound "forty-five-year-old" is a modern English construction built entirely from native Germanic elements. Its logic is transparently arithmetic and descriptive: it combines the cardinal numbers "forty" and "five" to specify a precise quantity, appends the unit "year," and concludes with the adjective "old" to denote age. Each component has a direct lineage to Old English, with "forty" deriving from the concept of "four tens," "five" from the basic numeral, "year" from a term for a cycle of seasons, and "old" from a root meaning "grown, adult." The hyphenated structure follows a consistent English pattern for forming compound adjectives and nouns that describe age, creating a single lexical unit from these sequential, literal parts.

Structure: forty (40) + five (5) + year (time unit) + old (aged) forty: From Old English 'feowertig', meaning four tens (40). A cardinal number. five: From Old English 'fīf', meaning the number 5. A cardinal number. year: From Old English 'gēar', meaning a period of twelve months. A noun. old: From Old English 'eald', meaning advanced in age. An adjective.