'playfulness' originates from English, formed from the word 'play' plus the suffixes '-ful' and '-ness', where '-ful' meant 'full of' and '-ness' meant 'state or quality of'.

'play' changed from Old English words 'plega' (noun) and 'plegian' (verb), through Middle English 'pleien'/'pleye', and eventually became the modern English word 'play'; 'playfulness' was later formed by adding '-ful' and '-ness' to express the quality of being playful.

Initially, 'play' meant 'sport, amusement' and referred to physical or recreational activity; over time it broadened to include any activity done for enjoyment and expression, and 'playfulness' came to mean the general quality or spirit of being playful.