Informal

• (a.) Not in the regular, usual, or established form; not according to official, conventional, prescribed, or customary forms or rules; irregular; hence, without ceremony; as, an informal writting, proceeding, or visit. • (a.) Deranged in mind; out of one`s senses.
Found on http://thinkexist.com/dictionary/meaning/informal/

informal

1. Not in the regular, usual, or established form; not according to official, conventional, prescribed, or customary forms or rules; irregular; hence, without ceremony; as, an informal writting, proceeding, or visit. ... 2. Deranged in mind; out of one's senses. 'These poor informal women.' (Shak) ... Origin: Pref. In- not + formal. ... Source: Web...
Found on http://www.encyclo.co.uk/local/20973

informal

loose adjective not officially recognized or controlled; `an informal agreement`; `a loose organization of the local farmers`
Found on https://www.encyclo.co.uk/local/20974

informal

[Adjective] Relaxed, not sticking to rules or formalities of dress or language.
Example: The college interview was very informal and students were encouraged to ask questions.
Found on http://www.bbc.co.uk/skillswise/glossary/

Informal

In·form'al adjective [ Prefix in- not + formal .] 1. Not in the regular, usual, or established form; not according to official, conventional, prescribed, or customary forms or rules; irregular; hence, without ceremony; as, an informal writing, proceeding, or visit. 2.
Found on http://www.encyclo.co.uk/webster/I/56

informal

not in accord with established conventions and requirements
Found on https://www.vocabulary.com/lists/418206

informal

[adj] - not officially recognized or controlled 2. [adj] - used of spoken and written language 3. [adj] - not formal
Found on http://www.webdictionary.co.uk/definition.php?query=informal
No exact match found