Vice President Bush yesterday defended his self-described "cheerleading" for President Reagan, saying in a nationally televised interview: "We don't consider loyalty in our family to be a character flaw."

"This president not only has title to my loyalty by definition of the job, but certainly has earned it through the way he has treated me," Bush said during his appearance on "This Week With David Brinkley" (ABC, WJLA).

"And so there's no question that's what I am loyal , and if some people want to say that's signing away something of the real me, too bad. Not gonna change."

Bush was responding to criticism of his defenses of Reagan's programs, including some that Bush opposed when running for the 1980 Republican presidential nomination. Among those who have attacked Bush is Democratic presidential candidate Walter F. Mondale.

"I couldn't be less interested in what Mr. Mondale in desperation is saying. He said ugly things about the president. He said ugly things about me," Bush said.

The vice president campaigned today with Reagan in Chicago, then flew to Texas to campaign for four GOP candidates for the House as part of the Republicans' drive to win congressional seats on the coattails of an anticipated presidential victory.

In the television interview, Bush also defended his wife, Barbara, who last month described Geraldine A. Ferraro, the Democratic vice-presidential nominee, as "that $4 million -- I can't say it but it rhymes with rich." Mondale later said the Bush family and staff were "conspiring" to undermine Ferraro's reputation.

"To have an opposition campaign, in desperation, try to rip her [Barbara Bush] into some kind of a conspiracy is absolutely patently absurd and grossly unfair," Bush said.

He also said that the national press did not give him enough credit for winning the debate with Ferraro.

Bush clarified an advertisement in which Reagan says he wants to cut taxes again. Asked if this means that the deficit-plagued government could operate on a still smaller share of the gross national product, Bush said: "I don't think that's what's envisioned." Reagan wants to "simplify" the tax system, he said.

Stung by an August controversy in which he said Reagan "would consider" raising taxes -- and then was accused of disagreeing with his boss -- Bush refused to expand on tax policy.

"I don't want to show a lack of manhood here in the last 48 hours," he said with a smile.