Eleemosynary

“Ambiguous”, because its meaning is uncertain.

Sorry, couldn’t resist.

Actually, one of my favorite words is “eleemosynary”, simply because it is SO arcane that it only shows up in places such as Jeopardy-type trivia games and graduate-school exams. Use it in an ordinary sentence, and once conversation resumes after a puzzled pause, your status as a word-geek will be fully cemented.