from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Open to doubt or challenge; problematic.
- adj. Not yet determined or specified.
- adj. Of dubious morality or respectability: a questionable reputation.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Problematic; open to doubt or challenge
- adj. Of dubious respectability or morality
from the GNU version of the Collaborative International Dictionary of English
- adj. Admitting of being questioned; inviting, or seeming to invite, inquiry.
- adj. Liable to question; subject to be doubted or called in question; problematical; doubtful; suspicious.
from The Century Dictionary and Cyclopedia
- Capable of being questioned or inquired of; inviting or seeming to invite inquiry or conversation.
- Liable to question; suspicious; doubtful; uncertain; disputable: as, the deed is of questionable authority; his veracity is questionable.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. subject to question
- adj. able to be refuted
question + -able (Wiktionary)