'suspiciousness' is correct and usable in written English
You can use it to describe a feeling or situation where something seems wrong or questionable. For example, "The detective noticed an air of suspiciousness among the group of people".
Persons who have a paranoid personality disorder show a pervasive and unjustified mistrust and suspiciousness of others.
Gustav was a harsh sovereign whose suspiciousness, irritability, and violence drove a succession of faithful servants into embittered exile.
Philip II's very consciousness of his divinely imposed obligations, compounded by his almost pathological suspiciousness of the intentions and ambitions of other men, had led him to deprecate independent initiative by his ministers.
His suspiciousness and capricious cruelty continued to grow, and wherever he went he had people tortured and executed.
He said that such open displays of animosity had been rare, though he sensed a certain suspiciousness about him on the street.
Scaring roused himself and the courtroom when he banged loudly on a table and said "Can you hear that?" and banged again, and again said, "Can you hear that?" He was mimicking a piece of theatre that Leventhal had performed during his cross-examination of Borukhova to emphasize the suspiciousness of her statement to the police that she had not heard the shots that killed Malakov.
We can't help noticing — as we did during other such works of the New Romanian Cinema as "The Death of Mr. Lazarescu" and "Four Months, Three Weeks, and Two Days" — a pervasive rudeness and suspiciousness, the malevolent hangover from many years of a police state.
The historian Richard Hofstadter's description of the far right in the era of Barry Goldwater could apply equally well today: "I call it the paranoid style simply because no other word adequately evokes the qualities of heated exaggeration, suspiciousness, and conspiratorial fantasy that I have in mind".
In an article in Harper's, Hofstadter described "the paranoid style in American politics," which he said was characterized by "heated exaggeration, suspiciousness, and conspiratorial fantasy".
He did not care in 1693 to cultivate what, centuries later, would be termed the paranoid strain in American politics, with its "sense of heated exaggeration, suspiciousness, and conspiratorial fantasy".
Marked by a pervasive suspiciousness and unjustified mistrust of others, this disorder is apparent when the individual misinterprets words and actions as having a special significance for him or as being directed against him.
