Synonyms of unconcluded

2 Syllables
baffling
3 Syllables
mystifying, difficult, unsolved, obscure, undone
4 Syllables
unfinished, trial-and-error, unsolvable, unresolved, insoluble, unfulfilled, unassembled
5 Syllables
unaccountable, unfathomable, inextricable, irresolvable, experimental, inexplicable, impenetrable
6 Syllables
indecipherable