casual

Strongly informal.

To a very high degree of informality.

To a moderate or reasonable degree of informality.

Nearly but not completely casual, sometimes implying a slight tension or effort.

Appearing to be casual, but perhaps not being so in reality.

Seeming casual on the surface, as far as one can see or understand.

Deliberately appearing informal, often to hide true feelings or intentions.

Seeming much more informal or simple than it really is.

To be relaxed and informal in manner, speech, or dress.

For one's voice to convey a relaxed and informal tone.

To give the impression of being relaxed and not overly concerned.

To be relaxed and not worried or serious about something important.