Confusingly, if the police suspect you of a crime, you can be described as a “suspicious person” and if you constantly suspect others of crimes, you can also be called “suspicious.” ... A suspect is a person somebody is suspicious of, never the person who is doing the suspecting.

Can you use suspect instead of suspicious?

Of course suspicious is always an adjective but suspect can be adjective, noun or verb. The police arrested the suspect. The police found a suspect parcel. His logic is suspect.

Is suspect short for suspicious?

Sus is a shortening of suspicious or suspect. In slang, it has the sense of “questionable” or “shady.”