ETYM Pref. in- not + formal.
1. Not formal.
2. Not officially recognized or controlled; SYN. loose.
3. Used of spoken and written language.

Množina: informal employments

Paid work on a casual basis. Jobs are irregular and people are often self-employed without pensions and without paying taxes.
This sort of employment is common in the urban areas of developing countries; for example, in Mexico City. It may involve service jobs of the tertiary industrial sector—shoe cleaning or selling bottled water—as well as craft industries. Informal employment also includes illegal activities such as theft, prostitution, and selling drugs.

Množina: informal meetings

Množina: informalities

A manner that does not take forms and ceremonies seriously.

Without formality; SYN. without formality.