noun
unresolved; shelved
Used in parliamentary or committee contexts when a bill or motion is left undecided and carried over to the next session. Often appears in news reports.
その法案は審議未了のまま会期終了となった。
The bill remained unresolved as the session ended.
廃案 means a bill is formally discarded, while 審議未了 means it is simply left undecided and may be revisited.
Compound of 審議 (deliberation) and 未了 (unfinished). The exact historical derivation is uncertain; the spelling is conventionally associated with legislative procedure.