'thought-out' originates from the combination of 'thought' and 'out', where 'thought' is the past participle of 'think', meaning 'to consider', and 'out' implies 'completion'.

'thought-out' evolved from the Middle English word 'thouht', which was derived from the Old English 'þoht', meaning 'consideration'.

Initially, it meant 'considered', but over time it evolved into its current meaning of 'carefully considered and planned'.