Joshua Nkomo is an angry, frustrated man.

In unceremoniously firing Nkomo from the Cabinet this week, Prime Minister Robert Mugabe has done the one thing that the proud Nkomo, who regards himself as the founder of black nationalism in this country, cannot tolerate. Mugabe has smeared the name of his one-time coalition partner and belittled his role in the struggle for black-majority rule.

Nkomo, accused of stashing arms to attempt a coup, has been stripped of his post as minister without portfolio and could end up in jail. His political party, the Patriotic Front (ZAPU), seems to have a bleak future in opposition.

There is little the humiliated leader of the Ndebele minority tribe can do to prevent his political demise. His only alternative is an impossible, suicidal one: calling his former guerrillas, now in the national Army under Mugabe's control, to arms, and there is little likelihood of it happening.

His main concern, revealed in a series of rambling interviews he gave this week in his home in the black Salisbury suburb of Highfield, is to preserve his status in the history of Zimbabwe's struggle for independence.

Ever since Mugabe began his personal attacks a week ago, calling his former coalition partner a "snake" and a "sellout," Nkomo has struck back in full-throated wrath. The response is doubtless in vain.

There is a sad beauty to his rage--like a flawed Greek hero shaking his first at the gods. Nkomo's immense bulk--he weighs about 300 pounds--adds to the drama.

As reporters watched and scribbled, Nkomo gripped his tribal stick and unleashed the full fury of his awesome temper Wednesday night minutes after journalists brought him the news of his firing. Perspiring under the heat of television lights, he trembled as he said:

"All this is an excuse to get rid of me from his Mugabe's government. And in doing so he tries to smear me. With all the work that I've done for this country, it can never be robbed by Robert Mugabe. Let him know that. He can't rob my work. He can do anything with me, but he will never, he will never." At that point his rising temper sputtered to a temporary halt, his lungs in need of breath.

Soon he charged on, calling Mugabe, only seven years his junior, a "politically hungry young man."

"He was talking a lie here about my name. Where do you see a prime minister who says those things and you can think that's a prime minister who can lead a country? It is a tragedy for this country."

The founder of the movement for black majority rule in the late 1940s, he complained that the government had seized his farm in the southwestern part of the country, his stronghold.

"I built my home there to rest after a struggle of 35 years while Mugabe was perambulating in West Africa," he said, an exaggerated reference to Mugabe's teaching in Ghana until 1960.

Referring to Mugabe's accusation that he sought to collaborate with South Africa in a coup attempt--a charge that would make him anathema to blacks everywhere on the continent--he blurted out: "He's telling a lie--a straightforward lie."

He complained that Mugabe had used him and now had thrown him out crudely.

"Why couldn't he just shake hands and say good-bye?" he asked.

Nkomo's problem is that Mugabe has him dead to rights. Large quantities of arms--enough to equip 3,000 to 5,000 troops--were found on property owned by his party.

Nkomo denied knowledge of the caches, but few believe him since he runs his Patriotic Front like a personal fiefdom.

He claims that arms were stashed all over the country by all sides as insurance if fighting broke out after Mugabe won power in April 1980. He is most likely correct, but that still leaves him with the burden of harboring weapons while being the junior coalition partner in the government.

Many members of Mugabe's party, the Zimbabwe African National Union (ZANU), have regarded Nkomo as a traitor during the years because he often talked secretly with various parties during the independence struggle--white prime minister Ian Smith, the South Africans and the Soviets.

Understandably, Nkomo has a different view, saying he was seeking a peaceful settlement of the seven-year guerrilla war.

He also has never forgiven Mugabe's followers for dividing the nationalist movement by pulling out of his party in 1963.

"Every time we have tried to have unity it has foundered on the rocks of ZANU," he said.

Any alliance was strictly one of convenience and was doomed from the beginning. Mugabe aligned himself with China, Nkomo with the Soviet Union. Their forces were deployed on opposite sides of Zimbabwe (then Rhodesia), in Mozambique and Zambia.

Even though the two men made a show of friendship at times, they were always an unlikely pair.

Mugabe, 57, is stiff, austere and formal. He often speaks over the head of his audience at rallies, somewhat in the manner of a university professor. There is a slight embarrassing hesitance when he waves his fist in a victory signal. He seems to live his socialist beliefs and does not display any signs of wealth.

Nkomo, although spouting socialism, is a capitalist in his life style and had large landholdings and business properties until they were confiscated by the government this week.

Speaking in rambling fashion, he has his audience eating out of his hand at rallies in his Ndebele home turf in southwestern Zimbabwe. He is treated like a king, and it is not uncommon for some admirers to prostrate themselves in front of him.

On a visit to New York three years ago, he brought along a young girl as a servant who brought him his meals, knelt before him and brushed crumbs from his suit when he was finished.

He once tried to expand his kingly role to the military sphere, showing up at a press conference in Lusaka, Zambia, in a specially tailored military uniform. There was no insignia of rank, but he wore a cap with lots of braid, "looking like a Bulgarian stationmaster," in the words of one journalist present.

Asked his rank, Nkomo said: "Me? Everybody knows I am commander-in-chief of ZAPU forces." He paused, chuckled and added, "on active duty." Conscious of the reporters' incredulity, he was never seen wearing the uniform again at a press conference.

Those who have experienced his notorious temper have watched in awe and trepidation.

"He flares quickly, but does not bear grudges," a longtime associate said. Within a few minutes of a spat he is usually laughing and has made up, the man added.

On the other hand, "If you tread on Mugabe's corns he can hit back hard and be bitter. He forgives but not in the same dramatic manner as Nkomo."

Mugabe, however, won the election and is firmly in power. Losers in African elections have a way of fading from sight.

What Nkomo wants is his reputation.

"I personally played a very big role in gaining independence , and Robert Mugabe should have the decency of honoring that," he said.