: in an insane manner : in a way that suggests unsoundness or disorder of mind
They sometimes gabbled insanely. One huge man was asking of the sky: "Say, where de plank road? Where de plank road!" It was as if he had lost a child. Stephen Crane
Glancing back, he saw all the carnage, death and misery he had caused in his career. The big rat laughed insanely and ran faster: on and on, past scenes of desolation and destruction … Brian Jacques
2
: to a very extreme degree
insanely jealous
insanely happy
insanely rich
The plot is insanely intricate. Terrence Rafferty
Justin Bieber … took to Instagram to show off the insanely expensive Audemars Piguet diamond watch he purchased for her as a birthday gift … Jane Meeker