Douglas Mwonzora, an parliamentarian for prime minister Morgan Tsvangirai's Movement for Democratic Change (MDC) and co-chairman of the key parliamentary constitutional commission, allegedly told MDC supporters that the 85-year-old Mugabe was a goblin.
The politician faces a maximum penalty of one year in jail if found guilty.
In Zimbabwean traditional mythology goblins are feared, hideous creatures with evil powers.
The joint head of the body meant to draft a new democratic constitution for Zimbabwe has been charged with insulting President Mugabe by calling him a goblin, lawyers confirmed Friday.
Mwonzora made the remarks nearly a year ago at a political rally ahead of presidential and parliamentary elections but was only summonsed on Monday this week, said lawyer Lewis Uriri.
The MDC won the elections but was then forced into a second round of the presidential ballot which was preceded by a wave of state-run violence that saw at least 100 MDC supporters murdered and thousands tortured and made homeless.
Mugabe was declared the winner after Tsvangirai withdrew because of the violence, and the poll was universally denounced as a fraud.
Shortly after, Southern African nations intervened to set up the inauguration of an unequal power-sharing government between Tsvangirai and Mugabe in which the autocrat controls the security forces.
Hundreds of people have been arrested and fined or jailed under Zimbabwean laws that make it an offence to make derisory comments about Mugabe, the world's oldest head of state who has been in power for nearly 30 years.
On Tuesday, an MDC provincial chairman in southern Zimbabwe was arrested for telling a party rally that the people must not allow Mugabe to cheat them in elections again.
The constitutional commission was set up under the coalition agreement, but progress has been bogged down by continual blockading by ZANU(PF) officials who, analysts say, fear they will be swamped in a democratic election held under a constitution guaranteeing human rights and the rule of law.