a. 1. Conceited; assuming; as, an upsetting fellow. [ Scot. ] Jamieson. [ 1913 Webster ]

2. such as to disturb the self-possession of; unnerving; causing mental distress; as, the sight was an upsetting experience. [ PJC ]

. A thermometer by merely inverting which the temperature may be registered. The column of mercury is broken and, as it remains until the instrument is reset, the reading may be made at leisure. [ Webster 1913 Suppl. ]