Błędnie: I would never suspect you of such debility. What you did was totally irresponsible and you're going to be in trouble. Poprawnie: I would never suspect you of such a stupid idea. What you did was totally irresponsible and you're going to be in trouble.
"Debility" to 'osłabienie fizyczne'. 'Debilizm' jako 'głupi pomysł, głupie działanie' to "a stupid/ foolish idea". 'Debilizm' w sensie niedorozwoju umysłowego tłumaczymy jako "imbecility' lub 'cretinism'.