From GNU Collaborative International Dictionary of English, version 0.54:
Ruse (?), n. [F., fr. OF. reüser, rehuser, to turn aside, to shuffle, retreat, fr. L. recusare to refuse; pref. re- again + causa cause. See {Cause}, and cf. {Recusant}.] An artifice; trick; stratagem; wile; fraud; deceit.
[1913 Webster]
‖Ruse de guerre (<?>) [F.], a stratagem of war.
[1913 Webster]