To ascertain the grammatical function of the emphasized word "bright" within the phrase "The bright light hurt his eyes.", perform the subsequent actions:
Determine the semantic value and grammatical function of "bright." In this context, "bright" serves to qualify the noun "light."
Words that describe or modify nouns function as adjectives.
Adjectives enhance understanding of nouns by detailing attributes like hue, dimension, or characteristic. Here, "bright" delineates the quality and visual aspect of "light."
Consequently, the appropriate part of speech for bright is Adjective.