the word "wooden" is a native english formation, built upon the old english noun "wudu," meaning "tree" or "the substance from trees." the suffix "-en" is an old english adjectival suffix used to indicate the material something is made from, as seen in other words like "golden" or "woolen." therefore, the literal meaning "made of wood" is direct and transparent. over time, the meaning extended metaphorically to describe people or movements that are stiff or lacking in natural flexibility, much like an object carved from wood.

Structure: wood (substance from trees) + en (made of, resembling) wood (old english, noun, the hard fibrous substance from trees); en (old english, adjective-forming suffix, meaning "made of" or "having the qualities of")