'erratically-guided' originates from the combination of 'erratic' and 'guided'. 'Erratic' comes from Latin 'erraticus', meaning 'wandering', and 'guided' is derived from Old English 'gīedan', meaning 'to lead'.

'erraticus' transformed into the Middle English 'erratik', and 'gīedan' evolved into the modern English 'guide'.

Initially, 'erratic' meant 'wandering', but over time it evolved to mean 'unpredictable', while 'guided' has largely retained its meaning of 'directed'.