fall-off

The compound noun 'fall-off' is a modern formation built from two deeply rooted Germanic elements. The verb 'fall' originates from Proto-Germanic fallaną, itself from the Proto-Indo-European root polh₂- meaning "to fall." The particle 'off' derives from Proto-Germanic af, from the PIE root h₂epó meaning "off, away." The literal combination, "to fall away," perfectly captures the conceptual logic of the word. It describes a process where something metaphorically drops away from a previous level, leading to its contemporary abstract meanings of reduction, decline, or deterioration in measurable or qualitative terms.

Structure: fall (to descend) + off (away, from) - fall: From Old English feallan, meaning "to drop from a height, fail, decay, die." Its functional role is as the core verb, providing the sense of a downward movement or decline. - off: From Old English of, meaning "away, away from." Its functional role is as an adverbial particle that modifies the verb, intensifying the sense of separation or reduction.