The origin of 'stubborn' is somewhat obscure but likely stems from Middle English. It may be related to the Old English verb 'styb(b)ian', meaning 'to be stunned or stupefied', which itself could be connected to a broader Germanic root related to being stiff or rigid. This conceptual link between physical stiffness and mental obstinacy is a common metaphorical pathway in language evolution. By the 14th century, 'stubborn' had firmly acquired its primary modern sense of unreasonably obstinate or inflexible, describing a person or attitude as difficult to bend or change, much like a stiff object.

The word 'stubborn' is a simplex word of Middle English origin. It is not productively formed from separable, meaningful morphemes in modern English. Its core is the Middle English adjective 'stiborn' or 'stoburn'.