(形容詞) 雖已決定把票投給哪位候選人，但對於自己的決定卻興趣索然，也沒把握這項決定是否正確。亦寫成 under-decided。
請注意 undecided 和 underdecided 的不同，前者是指還未決定投給哪位候選人，而後者是指已決定投給哪位候選人，但對於自己的決定卻激不起任何熱情，而且也不確定這項決定是否正確。
In some ways, schools are designed for people who have already made a decision about their major. That can make it uncomfortable for students who either are undecided about their major or have significant reservations about their current choice. If you are undecided or underdecided, realize that you have a great advantage over students "who know for sure" what they want to do.
—John A. Beck and Marmy A. Clason, Light on the Path, Wadsworth, September 11, 2007
I'll be honest, though, I'm pretty underwhelmed with this whole election. I know who I'm going to vote for, and I've known for a while, but I wish I could have been more excited about it. I don't fall into the "undecided" category, but I guess I'm looking for a reason to get enthused — for a reason to change my vote.
I've coined a word for this feeling — "underdecided."
—Grant Hamilton, "I would vote in advance, if...", Brandon Sun, September 26, 2011