The term gained significance in the recent Payton v. New York (1980) decision of the U.S. Supreme Court. The Court held that without exigent circumstances, the fourth amendment would prohibit the police from making a warrantless and nonconsensual entry into a suspect's home to make an arrest. Included are an analysis of Supreme Court precedent; an examination of the pertinent opinions of the Federal and State courts which, before Payton, had required for their jurisdictions exigent circumstances for such warrantless arrests; the proposed exigent circumstances formula of a noted commentator; and a suggested definition which meets the needs of the courts and law enforcement officials in the aftermath of Payton. The suggested definition is as follows: given probable cause to arrest and a reasonable belief that the suspect is in his home, exigent circumstances for a warrantless and nonconsensual entry into a suspect's home to effect this arrest exist when a reasonably prudent man in the circumstances would be warranted in the belief that delaying arrest to secure the warrant would pose a significant risk of danger to life or property, of the escape of the suspect, or of the destruction of evidence. The first portion of the definition regarding probable cause and a reasonable belief as to the suspect's location sets up as a prerequisite to warrantless home entries to arrest the same conditions when obtaining an entry premised on an arrest warrant. The requirement of a reasonable belief that delaying arrest to secure a warrant would pose a significant risk puts into effect the Court's desire that the risk of an exigency that a court should look for is generally described by the three situations which have been gleaned largely from Supreme Court cases -- danger to life or property, escape of the suspect, and destruction of evidence. Footnotes are included.