Not completed or finished; still in progress or incomplete.
From 'un-' (prefix meaning 'not') plus 'finished' (from Old French 'finir,' from Latin 'finire' meaning 'to end'). Simple negation of completion.
English loves adding 'un-' to almost any adjective to flip its meaning—'happy' becomes 'unhappy,' 'finished' becomes 'unfinished'—which is why English has so many negatives compared to other languages that might need whole different words!
Complete word intelligence in one call. Free tier — 50 lookups/day.