Antonym of 'Formalize'

Question

Is there an antonym for 'Formalize'?

As to make something not formal.
Would it be Deformalize, Unformalise, Informalize, or something else?

Answer 1

Deformalize is the correct term. The dictionary gives the origin and definition :

to make less formal; Origin: 1875–80; de- + formalize

However, the dictionary doesn't give records of unformalise or informalize

Answer 2

Deformalize and informalize both are synonyms and mean exactly what you are looking for - the antonym for formalize. Since informal is a well-known word (an antonym for formal), it should be easier for others to understand informalize than to understand deformalize.

Also note that as formal means being in accord with established forms, following a certain order, an antonym to this could also be disorder, which expresses an absence of order; state of not being arranged in an orderly manner.