the word 'uncurl' is a relatively modern english formation, built from the native germanic prefix 'un-' and the verb 'curl'. the base 'curl' entered middle english from middle dutch or low german 'crullen', which meant to curl or bend. the prefix 'un-', with its ancient proto-germanic root 'un-', carries a reversative sense, meaning to undo an action. therefore, the literal construction "reverse the action of curling" directly and logically yields the modern meaning: to straighten out from a coiled or curved state. it exemplifies the productive capacity of english to create new, transparent verbs by combining a native prefix with an assimilated root.

Structure: un (reverse action) + curl (form into a curved or spiral shape) un: a prefix of germanic origin (old english) meaning "not" or "to reverse an action". in this word, it functions as a reversative prefix. curl: a verb of middle dutch/low german origin (from 'crullen', meaning to curl). it functions as the base root describing the action of forming a curve or spiral.