The word "stinky" is a straightforward formation from the native English verb "stink." The root "stink" itself has ancient Germanic origins, tracing back to the Proto-Germanic verb stinkwaną, which meant simply "to smell," though it often carried a negative connotation. This Germanic root is further linked to the Proto-Indo-European base stengʷ-, meaning "to push, thrust, or sting," a semantic connection that evokes the invasive, penetrating nature of a strong odor. By adding the productive adjectival suffix "-y," the word "stinky" was formed to describe something that is characterized by or full of a stink, making its meaning transparent and logical within the English morphological system.

Structure: stink (to smell very bad) + y (adjective-forming suffix) - stink: From Old English stincan (to emit a smell, often bad). Its functional role is the core semantic root. - y: A native English suffix from Old English -ig, used to form adjectives meaning "characterized by; full of; having the quality of".