the word 'spindly' is a derivative of the noun 'spindle', which refers to a slender, tapered rod used in hand-spinning thread. the adjective-forming suffix '-y' was added in the 17th century to create a descriptive term. the modern meaning directly extends from the physical characteristics of a spindle—being long, thin, and often delicate—to describe anything, especially limbs or growth, that is unattractively tall and thin. it carries a connotation of frailty or awkwardness, moving from a concrete tool to an abstract quality of form.

Structure: spindle (a thin rod) + y (adjective-forming suffix) spindle (from old english spinel, meaning a rod for spinning thread, of germanic origin) + y (a native english suffix forming adjectives meaning "having the quality of").