'seldom-done' originates from the combination of 'seldom,' an Old English word 'seldan,' meaning 'rarely,' and 'done,' the past participle of 'do,' from Old English 'dōn.'

'seldan' transformed into 'seldom' in Middle English, and 'dōn' became 'done,' eventually forming the modern English compound adjective 'seldom-done.'

Initially, 'seldom' meant 'rarely,' and 'done' meant 'completed.' Together, they have maintained the meaning of 'rarely completed.'