In the European tradition, casual is the dress code that emphasizes comfort and personal expression over presentation,
Ceremonial dress such as royal robes and full dress military costume
Formal wear such as white tie.
Semi-formal such as black tie.
This time was most dreadful for Lilian. Thrown on her own resources and almost penniless, she maintained herself and paid the rent of a wretched room near the hospital by working as a charwoman, sempstress, anything. In a moment she had dropped to the level of a casual labourer.
It was a casual sneer, obviously one of a long line. There was hatred behind it, but of a quiet, chronic type, nothing new or unduly virulent, and he was taken aback by the flicker of amazed incredulity that passed over the younger man's ravaged face.