For Sandberg that may be an undefinable capacity yet it did play a vital role in her success.

FORBES: Connect

Their term, unlike that of financial options, is usually open-ended or undefinable.

ECONOMIST: Economics focus

They chose Smith because they had recently read her memoir, Just Kids, and were fascinated by the undefinable quality of the relationship she had with Robert Mapplethorpe.

WSJ: All the Ladies | Making It

It is easy to see what Bernanke is missing: he thinks that low growth and high unemployment create some undefinable something called an output gap, which leads to other undefinables called resource slackness, and these undefinables protect us from inflation.

FORBES: What Gold Sees, and Ben Bernanke Does Not