Proper, according to strict etiquette; not casual.
Official.
Relating to mere manipulation and construction of strings of symbols, without regard to their meaning.
Relating to formation.
Organized; well-structured and planned.
Being in accord with established forms.
Relating to the form or structure of something.
Ceremonial or traditional.
An event with a formal dress code.
Formalin.
A formal parameter.
An evening gown.
An acetal formed from formaldehyde.
Wearing a particularly stern and disapproving expression; humourless; priggish.
Poker-faced.