In a defeat for the Reagan administration, the Senate Labor and Human Resources Committee yesterday voted to reject the nomination of Jeffrey I. Zuckerman as general counsel of the Equal Employment Opportunity Commission.

Zuckerman, who was nominated last September, acknowledged in testimony earlier this year that he had said privately that blacks and women could overcome job discrimination by offering to work for lower wages than white males.

In a 10-to-5 vote, three Republicans, Charles E. Grassley of Iowa, Lowell P. Weicker Jr. of Connecticut and Robert T. Stafford of Vermont, joined the seven committee Democrats to kill the nomination. Sen. Paula Hawkins (R-Fla.) abstained.

Zuckerman, now chief of staff for EEOC Chairman Clarence Thomas, also came under sharp scrutiny at his confirmation hearings for having challenged a series of court rulings on age discrimination.

At a Dec. 10 hearing, he was asked about a 1984 memorandum in which he told Thomas that it was "reasonable" for a company making layoffs to dismiss employes who would receive retirement benefits -- despite federal court rulings finding that such layoffs constitute illegal age discrimination.

Zuckerman wrote in the memo: "It seems to me that eligibility for retirement is a reasonable factor other than age . . . . It seems to me reasonable for a company that must lay off employes to do so in a way that minimizes economic hardship on those laid off, by discharging first those who will receive retirement benefits."

During another hearing in March, Zuckerman said he had a "fundamental disagreement" with civil rights groups because he opposed hiring goals and timetables for women or blacks.

In a statement released after the vote, Zuckerman said, "I am deeply disappointed, but take solace from the fact that when Justice [John Marshall] Harlan said in 1896 that the Constitution of the United States is colorblind, he was voted down 8 to 1."

Thomas called Zuckerman a "fine lawyer" and said he was "disappointed and dismayed" by the vote.

Ralph Neas of the Leadership Conference on Civil Rights, which lobbied against the nomination, yesterday said, "Repeatedly, Mr. Zuckerman's actions were inconsistent with the fair application of the laws passed by Congress and interpreted by the courts . . . . This was a strong bipartisan rejection of [the administration's] extremism on civil rights."

Sen. Howard M. Metzenbaum (D-Ohio) said the administration should have nominated an individual with "a commitment to enforcing civil rights legislation." Although Zuckerman says he has that commitment, Metzenbaum said, "his actions belie his words."

"It's astounding the administration would nominate someone who has never litigated" a civil rights case, Metzenbaum said. "He has never dealt with the reality of how civil rights statutes are applied."

Chairman Orrin G. Hatch (R-Utah) defended Zuckerman, saying he had "agreed to expand the EEOC caseload" from its current level of two cases per attorney. Hatch said this demonstrated Zuckerman's commitment to civil rights enforcement.

Hatch also said there is case law to support Zuckerman's arguments against affirmative action. "If the Supreme Court would define these areas a little more," Hatch said, Zuckerman would enforce the high court's rulings.

On Monday, the Supreme Court rejected a Jackson, Mich., affirmative action plan that gave job preference to black schoolteachers over whites with more seniority. But in five separate opinions, the justices expressed strong support for the principle of affirmative action.

The EEOC is the agency responsible for examining complaints of employment discrimination, mediating disputes between employes and employers, and going to court to enforce laws against job discrimination.