The term 'get hot under the collar' is an idiom that means to become very angry or agitated. The crossword solutions for this term are ROAST (5 letters), FUME (4 letters), SEETHE (6 letters), BOIL (4 letters), SEERED (6 letters), and STEAMUP (7 letters). All of these words describe a state of extreme anger, with ROAST referring to being scolded, FUME referring to emitting smoke in anger, SEETHE referring to boiling with rage, BOIL referring to a state of intense heat, SEERED referring to becoming red in the face, and STEAMUP referring to becoming filled with steam.