adverb (r)

• without formality

  tanpa formalitas

  Example:
  He visited us informally.
  

  Antonym:
  formally
  

  source: wordnet30
• with the use of colloquial expressions

  dengan penggunaan percakapan ekspresi

  Synonym:
  colloquially, conversationally
  

  source: wordnet30
• In an informal manner.

  dalam satu cara informal.

  source: webster1913