Mid 19th century; earliest use found in Francis Galton (1822–1911), biostatistician, human geneticist, and eugenicist. From a first element imitative of the bird's call + -ing.
Definition of roocoocooing in US English:
roocoocooing
(also roocooing, roocoorooing)
nounruːkuːˈkuːɪŋ
The cooing of a pigeon or dove.
Origin
Mid 19th century; earliest use found in Francis Galton (1822–1911), biostatistician, human geneticist, and eugenicist. From a first element imitative of the bird's call + -ing.