'unhesitant' originates from the prefix 'un-' meaning 'not' and the word 'hesitant', which comes from Latin 'haesitantem', meaning 'to stick or hesitate'.

'hesitant' changed from the Latin word 'haesitantem' and eventually became the modern English word 'hesitant'. The prefix 'un-' was added to form 'unhesitant'.

Initially, 'hesitant' meant 'to stick or hesitate', but 'unhesitant' evolved to mean 'not showing hesitation'.