English thair

← Old English þearf (inherited)

← German darf (cognate)

← Middle English ther (inherited)

← Middle English thar (mention)

← Middle English tharr (mention)

← Middle English tharf (mention)

← Proto-Germanic *þarf (inherited)

← Proto-Germanic *þurbaną (derived)

← Proto-Indo-European *terp- (derived)

← Icelandic þarf (cognate)

← Dutch durf (cognate)

← Norwegian tarv (cognate)