Verb
(idiomatic) To be required to, ought to, expected to
I am supposed to report to the police every week.
Paul is supposed to call his mother every day.
(idiomatic, with not) To be permitted to.
I am not supposed to smoke there.
(idiomatic) To intended to; to be expected to; to believed to.
It's supposed to rain.
The thief is supposed to be hiding in the forest.
(idiomatic, in interrogative or similar situations) To be expected to; to be capable of (used to indicate that an expectation is impossible or unreasonable in the context).
How am I supposed to work in all this racket?
What was he supposed to do—just sit there and do nothing?
That no government, so called, can reasonably be trusted for a moment, or reasonably be supposed to have honest purposes in view, any longer than it depends wholly upon voluntary support. Lysander Spooner
He was very much a man of moods, possibly owing to what is styled the artistic temperment. I have never seen, myself, why the possession of artistic ability should be supposed to excuse a man from a decent exercise of self-control. Agatha Christie
Every one must be supposed to be cognizant of a public law. Edward Law, 1st Baron Ellenborough
A common mortal periodically selected by his fellow-citizens to watch over their own interests, can never be supposed to possess this stupendous virtue. William Godwin
The vast majority of English folk cannot and will not consider a picture as a picture, apart from any story which it may be supposed to tell. James McNeill Whistler
Any possible universe could be explained as the work of some sort of designer. Even a universe that is completely chaotic...could be supposed to have been designed by an idiot. Steven Weinberg