a bright spark

a bright spark

  (British & Australian)
an intelligent person
Usage notes: This phrase is often used humorously to mean the opposite.
Some bright spark was clearing up and threw my invitation away.
See also: bright, spark
References in classic literature ?
The wonderful turmoil went on--presently a bright spark sprung from a blade, and that blade broken in several pieces, sent one of its fragments flying to the ceiling.