Sharp or biting, as in character or expression. “The director occasionally allowed an acerbic tone to an otherwise subtle dialogue.”

1. Difficult to understand; abstruse. 2. Not publicly disclosed; confidential. 3. Of rare, special, or unusual interest. “Her software’s success was based on an esoteric programming language.”

Menacing; threatening. “Ominous black clouds;” “An ominousscream prior to the shooting.”

One that is out of its proper, chronological, or historical order, especially a person or practice that belongs to an earlier time. “A sword is an anachronism in modern warfare.”

 1. Lacking definition or definite content. 2. Lacking definite form or limits; vague. “The test results were nebulous and determined to be unusable.”

 To make more violent, bitter, or severe; to irritate or make worse. “The continued delays were greatly exacerbated by the lack of workers on the project.”

Relating to, or limited by time. Lasting only for a time; not eternal.  Also: fleeting, passing, momentary, temporary, transient, short-lived. “The beneficial effects of the loan were temporal.”

More concerned with practical results than with theories and principles. “The CEO used a pragmatic approach to making his business a success.”

Extremely small in size; tiny. A very small person or thing. “Although diminutive in stature, they were a formidable opponent;” “A diminutive report.”

Hard-working; industrious. Marked by or requiring long, hard work. “It was a laborious project, but they still kept it under budget.”