The word 'too-bright' is a modern English compound adjective formed by combining the intensifying adverb 'too' with the adjective 'bright'. The adverb 'too' traces its lineage to the Old English 'tō', which originally meant 'in addition to' but evolved to signify an excessive degree, a semantic shift that occurred by the 16th century. The adjective 'bright' descends from the Proto-Germanic 'berhtaz', itself from the Proto-Indo-European root 'bhereg-', meaning 'to shine, white, bright'. The compound logically fuses these elements: the ancient concept of shining light is modified by the notion of excess, creating a term that describes a luminosity so intense it becomes uncomfortable or glaring. This follows a common Germanic pattern of creating descriptive compounds where an adverb specifies the manner or degree of the core adjective's quality.

Structure: too (excessively) + bright (shining) - too: From Old English 'tō', an adverb meaning 'in addition, also, excessively'. In this compound, it functions as an intensifying prefix indicating an excessive degree. - bright: From Old English 'beorht', 'bryht', meaning 'shining, splendid, clear-sounding'. It functions as the core adjective describing the emission or reflection of light.