Meaning : A standard for judging when freedom of speech can be abridged.
Example :
No one has a right to shout `fire' in a crowded theater when there is no fire because such an action would pose a clear and present danger to public safety.
Clear and present danger ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Hindi. Clear and present danger ka matlab kya hota hai?