Even keel is technically an idiom which means everything is stable or under control. A related idiom is smooth sailing. Both idioms have their origin in boating or sailing. For a ship to be on an even keel is for it to be level in the water and sailing smoothly.
Even keel may be used on its own or in the phrase on an even keel. The second phrase is found in some dictionaries, while the first is not. It is always spelled as two words with no hyphen. Alternatively, even-keeled is listed in some dictionaries as an adjective meaning smooth or stable.
This phrase is surely one that is in transition. If you are particularly worried about your audience, stick with the adjective or the full phrase on an even keel. This is especially true for those outside the United States, where the transition does not seem to be as prominent. Otherwise, feel free to use the up-and-coming even keel.
Examples
Russia may be among the worst hit by the decline in oil prices, but analysts say clean living may keep government finances on an even keel. [CNBC]
A few weeks ago, this column indulged in a little bit of devil’s advocation, asking whether a profit-oriented pragmatist such as Ashley wasn’t exactly what Rangers needed to get them running on an even keel, rather than the regimes who openly admitted to blowing £67m in 18 months. [Daily Record]
On the court and in front of a microphone, the 40-year-old is even keel and monotone, getting through his debut season without a technical foul. [New York Daily News]
“Am I Wrong” is so even-keeled that it’s like riding in the most sepia-toned car commercial that a marketing executive could dream of. [Billboard]