Collocation Dictionary
Common collocations with insane in American Collocation
completely
absolutely
completely
quite
totally
utterly
Are they totally insane?
The whole idea is utterly insane.
rather
rather
slightly
somewhat
It all sounded slightly insane.
in a particular way
clinically
criminally
He was in a prison for the criminally insane.
be
be certified
become
be declared
be driven
go
seem
sound
She knew she must get help or she would go insane.
This probably sounds insane from a common-sense point of view.