informal

adj

1. Not formal or ceremonious.

   “an informal get-together”

   “One saint's day in mid-term a certain newly appointed suffragan-bishop came to the school chapel, and there preached on “The Inner Life.” He at once secured attention by his informal method, and when presently the coughing of Jarvis […] interrupted the sermon, he altogether captivated his audience with a remark about cough lozenges being cheap and easily procurable.”

   “Students and faculty members lunch at the cafeteria and naturally communicate freely with one another in a relaxed and informal setting.”

   “Participants emphasized the importance of their social network in facilitating their strength training experiences. Family members served as informal coaches who introduced the participants to basic exercises. This role, where family members model healthy behaviors, has been identified as being important to help supporting PA participation among autistic individuals in prior work (Ku et al., 2020; Shields et al., 2012).”

2. Not in accord with the usual regulations.

   “an informal agreement”

3. Suited for everyday use.

   “informal clothes”

4. Reflecting everyday, non-ceremonious usage.

   “When I returned to the movie Ghilli, a Kollywood classic (Kollywood being the informal name for Tamil cinema) that I loved as a kid, I couldn’t help but question why the story continues romantically, without question, after the heroine is slapped by the supposed love of her life.”

5. Not organized; not structured or planned.