Collocations for illusion - noun

dangerous
To believe you have nothing more to learn is a dangerous illusion.

optical, visual
The road ahead looks wet, but in fact this is an optical illusion.

be under, entertain, have
They are under no illusions about the difficulties ahead of them.

create, give (sb)
The huge size of the vehicle gives the illusion of safety.

foster, maintain, preserve, sustain
They are trying to maintain the illusion that the company is in good shape.

break, destroy, dispel, shatter
Within the first week at university all my illusions were shattered.

shed
Now is the time to shed our illusions.

~ about/as to
She had no illusions about her attractiveness to men.

be all an illusion
It turned out that their happy marriage was all an illusion.