A founder of the Grin party has vowed to file a petition with the Central Administrative Court after the Election Commission told the party to change its name in 15 days.
Sombat Boonngam-anong, a red-shirt activist, posted photos of the EC's two-page letter he had received on Facebook on Friday evening.
The letter, dated Wednesday and signed by EC registrar Jarungwit Poomma, says the party's Thai name (pronounced "Grean") has three meanings, citing Royal Society dictionaries.
First, it refers to a crew cut or haircut close to the head or trimming something to its surface. Second, it means a crude mixture of flour and water, or fine broken rice. Third, it's the name of a type of large trees with white- or lavender-coloured flowers.
The letter also refers to the slang meaning of the word widely used in recent years.
"It refers to a person or group of persons who are aggressive, inconsiderate and irrational.
"A Royal Society new-word dictionary also says the word is used to describe a person who is 'aggressive, belligerent and irrational'," reads the letter.
The EC claims the ambiguous meanings of the name could confuse the public. It may therefore be inappropriate, disrupt public order or affect the good morality of people. As a result, the name could violate Section 38 of the 2017 Political Parties Act.
For these reasons, the EC asked the applicants to change the name and submit documents to the EC 15 days after receiving the letter.
Failure to act within the period will result in the application being turned down, the letter says.
Mr Sombat, who applied to form the party with Decharut Sukkumnoed, a Kasetsart University lecturer, wrote on Facebook he had issues with the EC's choice of the definitions.
"I thought about it all night and believe the EC might have used imagination in considering our party's name even though we state clearly several times that it means 'short, orderly, concise, clean and without ticks'," he wrote.
Although this may sound trivial, Mr Sombat believes it's a matter of principle. "We have every right and freedom to name our party any which way we like."
"We'd like to use this opportunity to set a new standard for the EC by bringing the case to court. We want to see the fight based on reasons, not imagination.
"Let's meet in the Central Administrative Court," he concluded the post. He wrote in another post urging people to join him at the court at 10am on Monday.
Mr Sombat applied to register the party on March 21. He earlier posted on Facebook urging anyone who agreed with his idea of setting up a party to meet him at the EC office on that day. He admitted he did not have the required 15 people to apply at the time and if not enough people showed up on that day, he would give up the idea.
Twenty-four people finally showed up and he declared success in his first step. He later had more than 500 people informing him they wanted to be members.
Mr Sombat said then the Grin party, whose campaign platform is based solely on social media, would bring "entertainment" to Thai politics and would focus not on campaigning for votes but on "picking fights".
He said he intended for Grin to be a "mass party" and policies would come from brainstorming among people who care to join.
In recent months, he worked on brainstorming ideas of addressing the rabies issue including how to build shelters for some 1 million stray dogs.