(ˈ)in, ən+ adjective
Etymology: in- (I) + formal
1. : not formal : conducted or carried out without formal, regularly prescribed, or ceremonious procedure : unofficial
informal hearing
informal discussion
informal contract
informal inquiries
informal gathering of friends
2. : characteristic of or appropriate to ordinary, casual, or familiar use
informal English
genial, informal manner
informal essay
3. obsolete : deranged , mad
poor informal women are no more but instruments — Shakespeare
4. of a design : having an asymmetrical composition or arrangement made from unequal shapes and distances
informal balance in a stage set