Definition of lone gunman in English English dictionary
An individual person who acts on his or her own initiative, without partners, especially one who has sole responsibility for doing something questionable, confidential, or iniquitous
The Wilson family had been sorely conflicted because each member had gone off in his or her own direction, thinking that they were all lone gunmen.
() From the Warren Commission's lone gunman theory, that the assassination of U.S. President John F. Kennedy was the work of a single individual, subsequently applied to numerous other political assassinations and shootings.