From The Collaborative International Dictionary of English v.0.48 :
Insanely \In*sane"ly\, adv.
Without reason; madly; foolishly.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
insanely
adv 1: in an insane manner; "she behaved insanely"; "he behaves
crazily when he is off his medication"; "the witch
cackled madly"; "screaming dementedly" [syn: insanely,
crazily, dementedly, madly] [ant: sanely]
2: (used as intensives) extremely; "she was madly in love";
"deadly dull"; "deadly earnest"; "deucedly clever"; "insanely
jealous" [syn: madly, insanely, deadly, deucedly,
devilishly]