Disturbance, Disturbed, Dogging, Drag, Drawback, Embarrassment, Enigma, Essence, Evil, Exasperation, Facer, Failing, Failure, Fault, Feeler, Fix, Flaw, Foible, Frailty, Gist, Harassment, Harrying, Head, Headache, Heading, Hole, Hounding, Illustration, Imbroglio, Imperfection, Inadequacy, Inconvenience, Incorrigible, Infirmity, Inquiry, Interrogation, Interrogative, Interrogatory, Intractable, Issue, Jam, Kink, Knot, Leader, Maladjusted, Matter, Meat, Mess, Molestation, Motif, Motive, Muddle, Mystery, Nuisance, Nut, Obstreperous, Perplexity, Persecution, Perturbation, Pest, Pickle, Plight, Point, Poser, Predicament, Puzzle, Puzzlement, Puzzler, Query, Question, Refractory, Riddle, Ado, Aggravation, Annoyance, Anxiety, Baffle, Bafflement, Basis, Bedevilment, Bewilderment, Blemish, Bore, Bother, Bug, Bugbear, Burden, Case, Catch, Catechism, Chapter, Complication, Concern, Confusion, Conundrum, Count, Crack, Crux, Defect, Defection, Deficiency, Delinquent, Demand, Devilment, Difficult, Difficulty, Dilemma, Disadvantage, Disconcert, Rift, Rubric, Scrape, Shortcoming, Snag, Stew, Sticker, Subject, Substance, Taint, Text, Theme, Topic, Trial, Trouble, Uncontrollable, Ungovernable, Unmanageable, Unruly, Upset, Vexation, Weakness, Why, Worry