Having a high temperature, in literal and figurative use.
hot button a topic or issue that is highly charged emotionally or politically; the term is recorded in the US as a marketing term from the early 1970s.
hot cross bun a bun marked with a cross and containing dried fruit, traditionally eaten on Good Friday.
hot-desking the practice in an office of allocating desks to workers when they are required or on a rota system, rather than giving each worker their own desk; the usage as a working practice is recorded from the early 1990s.
hot potato a controversial issue or situation which is awkward or unpleasant to deal with.
hot-stove in North American usage, a discussion about a favourite sport carried on during the off season; the expression (recorded from the 1950s) is associated with discussions conducted around a heater in the winter.
See also blow hot and cold, like a hot knife through butter, a little pot is soon hot, strike while the iron is hot.