'substandardly' originates from the prefix 'sub-' meaning 'below' and the word 'standard,' which comes from Old French 'estandart,' meaning 'a rallying place or object.'

'substandard' evolved from the combination of 'sub-' and 'standard,' and 'substandardly' was formed by adding the adverbial suffix '-ly.'

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