'tight-knit' originates from the combination of 'tight' and 'knit', where 'tight' meant 'firmly held' and 'knit' meant 'to join closely'.

'tight-knit' evolved from the Old English word 'cnyttan', meaning 'to tie or bind', and eventually became the modern English word 'knit'.

Initially, it meant 'closely bound together', and this meaning has largely remained the same in modern usage.