informal

UK: ɪnˈfɔːməl | US: ɪnˈfɔːrməl

Definition
  1. adj. not formal or ceremonious; casual

  2. adj. (of language) suitable for everyday conversation but not for official contexts

  3. adj. (of an organization or event) without strict rules or structure

Structure
in <not>form <shape>al <adjective suffix>
Etymology

The word "informal" originates from Latin roots. The prefix "in-" (meaning "not") negates the root "form" (from Latin "forma," meaning "shape" or "structure"). The suffix "-al" turns the word into an adjective. Historically, "formal" referred to things adhering to established structures or rules, so "informal" emerged to describe the opposite—relaxed, unstructured, or casual contexts. The term reflects a shift in societal attitudes toward rigid conventions, allowing for more flexible interactions.

Examples
  1. The meeting was informal, with everyone dressed casually.

  2. Avoid using informal language in academic writing.

  3. The club has an informal atmosphere, making new members feel welcome.

  4. She sent an informal email to her colleagues about the schedule change.

  5. Their relationship started as an informal friendship before growing into something deeper.