'instantly-gained' originates from the combination of 'instant' and 'gain', where 'instant' meant 'immediate' and 'gain' meant 'to acquire'.

'instantly-gained' evolved from the Middle English word 'instaunt' and 'gainen', eventually becoming the modern English term 'instantly-gained'.

Initially, it meant 'acquired immediately', and this meaning has largely remained the same in modern usage.