This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

v. Simple past tense and past participle of formalise.

adj. given formal standing or endorsement; made official or legitimate by the observance of proper procedures

adj. concerned with or characterized by rigorous adherence to recognized forms (especially in religion or art)

"No agenda for this meeting was ever formalised, which is hardly surprising, but its purpose was twofold."

official