na-adjective, noun
uncertain; indefinite; undetermined
Describes something not yet fixed, decided, or confirmed. Often used in formal or technical contexts such as schedules, plans, or scientific observations.
会議の日程はまだ不確定です。
The meeting schedule is still uncertain.
不確定な要素が多い計画だ。
It's a plan with many uncertain factors.
未定 means 'undecided' or 'not yet fixed', often used for schedules or plans, similar to 不確定 but slightly more common in everyday contexts.
Compound of 不 (not) + 確定 (decision, confirmation). The word follows standard Sino-Japanese word formation patterns.