colloquial
adjective /kəˈləʊkwiəl/
  /kəˈləʊkwiəl/
- (of words and language) used in conversation but not in formal speech or writing synonym informalOxford Collocations DictionaryColloquial is used with these nouns:
- expression
 - language
 - phrase
 - …
 
Word Originmid 18th cent.: from Latin colloquium ‘conversation’ + -al.