futile
The definition for futile is "Without purpose, completely ineffective." Used in a sentence: Arguing with Andrew is futile because he never changes his mind.
incidental
The definition for incidental is "Minor." Used in a sentence: The accountant advised Justine not to report her incidental expenses.
incongruous
The definition for incongruous is "Not harmonious, incompatible." Used in a sentence: Sadie's cowboy hat was incongruous with her black cocktail dress.
oblivious
The definition for oblivious is "Lacking awareness." Used in a sentence: Love–struck Charlie was oblivious to everyone but the object of his affection.
trove
The definition for trove is "Valuable collection." Used in a sentence: Walter's trove of vintage baseball cards was worth thousands of dollars.