'unconstitutional' originates from the prefix 'un-' meaning 'not' and the word 'constitutional', which comes from 'constitution', derived from Latin 'constitutio', meaning 'arrangement' or 'establishment'.

'Constitutional' evolved from the Latin 'constitutio', through Old French 'constitucion', and eventually became the modern English word 'constitution'. The prefix 'un-' was added to form 'unconstitutional'.

Initially, 'constitution' referred to the act of establishing or arranging, but over time it evolved to mean the fundamental principles or established precedents according to which a state is governed.