AMES, Iowa — “UNBECOMING.” “Miss Congeniality.” Not sufficiently “ladylike.” In politics, these words and phrases have long been used to belittle female candidates. But now, female politicians are increasingly trying to rethink — and reclaim — how language shapes how they are perceived.

Recently, Senator Claire McCaskill, Democrat of Missouri, trained her sights on a single word — “ladylike.” “Ladylike,” Ms. McCaskill told an audience at Iowa State University last month, means, “Speak out, be strong, take charge, change the world” — all traits she thinks female leaders, or even the first female president, should have, and characteristics she believes are “very, very ladylike.” The term had a very different meaning when, during her 2012 re-election campaign, her opponent, Todd Akin, then a representative, described her performance during a debate as not particularly “ladylike,” and “very aggressive.”

Ms. McCaskill joins a long line of powerful women who are trying to use gender-based words to their advantage. Bella S. Abzug, a feminist and antiwar activist, first ran for Congress in 1970 with the slogan “This woman’s place is in the House — the House of Representatives!”

In 2002, when Mitt Romney ran for governor of Massachusetts against Shannon O’Brien and described her debate performance as “unbecoming,” Ms. O’Brien derided him as a sexist, and Hillary Rodham Clinton and Teresa Heinz Kerry held a rally on her behalf, praising all the “unbecoming women” who turned out in support. And Senator Patty Murray, Democrat of Washington, began her political career after a state lawmaker dismissed her as “just a mom in tennis shoes.” The insult prompted Ms. Murray to run for the Senate — and she adopted “mom in tennis shoes” as a campaign motto she still uses.