'unconstrained' originates from the prefix 'un-' meaning 'not' and the word 'constrained' from Latin 'constringere', where 'con-' meant 'together' and 'stringere' meant 'to bind'.

'constringere' transformed into the Old French word 'constraindre', and eventually became the modern English word 'constrain', with 'un-' added to form 'unconstrained'.

Initially, 'constringere' meant 'to bind together', but over time, 'unconstrained' evolved to mean 'not restricted or limited'.