full-strength

The compound adjective "full-strength" is a transparent combination of two native English elements. "Full," with Proto-Germanic origins meaning "full" or "plenty," acts as an intensifier to modify the noun "strength," which derives from the Proto-Germanic root strangithō, meaning "power" or "force." The term's logic is entirely literal, directly combining the concepts of completeness and potency. Its modern applications, whether describing an undiluted beverage or a military force at maximum capacity, retain this core sense of being at the peak of inherent power or concentration, with no reduction or dilution.

Structure: full (complete) + strength (power) full: From Old English full, meaning "containing all that can be held; complete, entire." It functions as an intensifier in this compound. strength: From Old English strengþu, strengþ, meaning "bodily power, force, vigor." It is the noun form and the core concept being modified.