After five full days of deliberations, a U.S. District Court jury yesterday convicted John A. Shorter Jr., a prominent District of Columbia criminal defense lawyer, of six misdemeanor counts of failing to pay $89,237 in income tax, and continued deliberations on the more serious charge of tax evasion.

The jury of seven women and five men found Shorter guilty of six counts of failing to pay taxes from 1978 to 1983. The government has charged that Shorter owes a total of $287,600 in taxes, fines and penalties for 1972 to 1983, and that he paid only $3,500 of $134,866 he allegedly owes in taxes for that period.

In June, Shorter pulled out of a plea bargain arrangement in which he was to plead guilty to the charges of failure to pay taxes in exchange for the government's agreement to drop the felony tax evasion charge.

Shorter, 58, who represented himself after dismissing two teams of lawyers, declined to comment on the verdict. He had argued that he was not guilty because of a lifelong addiction to gambling that he said compelled him to spend his money.

But prosecutors Carol E. Bruce and Darryl W. Jackson argued that Shorter deliberately evaded taxes by living a "cash life style" and hiding his assets in bank accounts under the name of his law partner.

Shorter faces a maximum sentence of one year in prison on each of the six counts of failure to pay taxes.